Power up for Humans

I am a firm believer that regular human beings similar to us in the real world can get much stronger if they applied themselves to certain fields of combat.

1. Kaio-ken - This is obviously the best way for humans to get stronger. Even just by multiplying their power by 20X can mean the difference against vastly stronger opponents. The likes of Goku can easily pass the skill to Krillin and Tien so that their students can benefit from this.

- Zen Kaio-ken: A unique variant of kaioken that multiplies a single physical trait. For instance you can just solely multiply "speed" instead of with everything else that is physical like strength, grip, endurance, etc. What great about this is that one does not become more exhausted upon consecutive use and the user can raise the multiplication even higher compared to the original kaioken. So if the users max was 5X, he can push the limits to 20X for that single trait since his entire body is not stressed out.

2. Cyborg Enhancements - If made by Dr. Gero, a normal human will instantly become as strong as a super saiyan. Major difference. And if enough training is made, the level to reach SSJ3 or even the gods is possible. Benefits includes a unlimited ki supply, immune to ki detection, age slowly, and only need water and oxygen to live. A wonderful cheating device for the human race if such technology ever became mass produced.

- Energy Absorption Model: Instead of being the superior unlimited energy type, the human becomes a android similar to Dr. Gero himself. Having a finite energy type, total depletion of resources will cause user to malfunction. Other benefits carries over.

3. Reincarnation - Honestly this is probably one of the greatest ways to start a new era of humans. If a single human being can be reborn from the soul of a previous entity (like Uub), it is possible said human can have a unique transformation never before seen. And upon reproduction, the genes that carries the form can be passed down. For example, Uub unlocks a form inside that brings out traits similar to Kid Buu. After fusing with Fat Buu and mastering this form, he gets married and has kids. The inherited majin cells are passed down and the offspring can use this form once they meet the right conditions. Same can be applied if humans are reincarnated from saiyans, nameks, demons, or even kaioshin.

4. 100% Full Power - Just like Master Roshi, humans can increase their ki by pumping ample amounts of energy into their muscles. Speed however will suffer.

- Lesser Percentages: Be able to use your power in increments akin to Frieza's own usage. So 0-1% is your base level with 50% being your halfway powered up state.

- Instant Switching and Partial Mass Manipulation: A variant where you are able to go from 100% to 1% instantly for surprise attacks or being able to pump up a body part exclusively at 100%. For example, you solely make your arm go to 100% to attain greater arm strength briefly.

5. Shapeshifting - Akin to both Puar and Oolong, humans can simply transform into anything they want to be. But since their power level does not change, perhaps modifications can be made to make it possible. For instance Yamcha transforms into his spirit animal, a wolf, which unlocks more of his latent potential.

6. Unlocked Potential - Either from the likes of good entities such as Grand Elder Guru and Elder Kai or from evil beings like Babidi, Towa, or Demigra, said human will get a boost that either permanent or temporary. The Ultra Divine Water or a wish from a Eternal Dragon are alternative methods. Very useful depending on the circumstances.

- Ultimate/Mystic Form: A power up gained by going through Elder Kai's ritual. Depending on the individuals potential, a moderate boost (decent small tier up or to SSJ powers) to levels surpassing a super saiyan 3 multiplier are possible to have for human beings. If human users has godly ki beforehand, the potential unlocked will make the user strong enough to fight against potential high tier godly opponents such as GoD agents (like Frieza) and candidates (like Toppo). The ritual can only be performed once, though the achievement of godly ki allows another ritual dance to occur since the users latent potential has evolved from last time. Side perks includes the opportunity to become a supreme kai disciple, thus attaining healing powers, sealing powers (like Mafuba), instantaneous movement, unique powers (dragon fist, etc), and use godly items (such as potara earrings, z sword, or the time ring). Interesting there are two variants to this power up. The first one is that this power up is "permanent", meaning that the user in question will remain in this state forever. All transformations besides ones that surpass the Ultimate state will become obsolete or impossible to use, though their power is forever accessible to the user in base form. Training, natural growth, and high-tier transformations is still possible. Also no power corrosion takes place, thus guaranteeing the user to always retain their acquired power over time. So a "lack of training" is no longer a danger. The second variant however acts like a "transformation", meaning the human user transforms into their ultimate state. Usually dubbed as the Mystic or Awakening form. Ultimately this is similar in usage to Gohan in both Fusion Reborn, Wrath of the Dragon, and Battle of Gods movies. All other transformations to the user are still easily accessible, though it is unknown if all of these forms are compatible with the ultimate state. If the user in question has a unnaturally large amount of latent potential, said ultimate form will be split into "7 levels", akin to Gohan's usage in FighterZ. Level 0 is effectively the user in base form. So no changes occur. But Levels 1 to 3 allows the human to reach levels equivalent to high-tier super saiyan multiplications. First signs of changes is sterner eyes, thinner chin strap, harder facial expressions, and a flowing white aura. Levels 4 to 6 grants the human users powers equivalent to high super saiyan 2 multiplications. New changes is a more muscular physique, hair change, and a lighter tan. Usual mental changes is more overconfidence and being procrastinating and haughty, though they can be negated with fine mental training over emotions. Level 7 however grants the user a power multiplication equivalent to super saiyan 3. So bio-electricity with a hint of energy glitter is visible. But again no additional strain, rage inducement, or energy cost is made for the entire transformations duration, thus making it a form with no true setbacks that can be used indefinitely (unless during sleep or death). However one true drawback is instated, and that is the fear of losing access to the Ultimate Form via lack of maintenance (retaining) and training (advancing in power).

- "Super Mystic Form" - If the human has godly ki and takes the "transformation" path, a "Level 8" is achieved that can become the humans equivalent to a GoD candidate's own hakaishin-like transformation. During such a state, the aura becomes dual-colored, outline is colored, voice becomes deeper, and the users strength increases dramatically. However a time limit is set up that automatically disables the form when the time limit is reached. And upon using Level 8, the users mentality usually becomes more sterner and serious, but mental training can be done to make the user more relaxed and less intuitive to their heightened instinctual drives and edginess. But it the user has the "permanent" selection, the users base power is forever like a psuedo's Gods of Destruction.

[Note]: If a Mystic Form user does become a Supreme Kai Disciple, not only will they gain additional training (specifically designed for kaioshins), techniques, and weapons, but will gain a unique set of clothing that has strong ties to the attire of a kaioshin. However even before this stage, to attain the right to undergo the ritual by Elder Kai, they must be pure of heart. If not up to standard, Elder Kai [or a Grand Supreme Kai] will perform a "mental fission" on the user to force him to defeat his fractured and split "evil half", dubbed "Ego". If victorious, the plan to get your potential unlocked shall be carried on. Surviving the over 24 hour ritual is the only remaining thing separating the user from achieving greater power. But if failed in the battle, your "evil half" will automatically merge with you and you will not receive your unlocked potential blessings.

7. Supreme Kai - Despite the fact most Supreme Kai's are shinjin (core people) born from the unique gold fruits on Kaishin from Kaiju trees, it is possible that regular shinjin's holding the rank of "Kai" (like Chronoa or Zamasu) can achieve this rank and all of its unique blessings. However it has been shown in Dragon Ball Fusions that other races can attain this state, such as Majin Ratopa through unknown means. So hypothetically speaking it is possible for human beings to attain this privileged rank as well. For how I see it, the human first needs to prove himself in both valor and strength. This is only acknowledged if the human has both his potential unlocked and is a supreme kai disciple. Upon achieving both, the supreme kai (or grand if there is more than two active kais) will perform a "life transfusion" to transfer his entire life force to the recipient. Upon completion and collapse, the supreme kai's body magically reverts into a golden fruit, and is subsequently eaten by the human. Immediately all inherited knowledge, powers of the supreme kai (godly ki if not already achieved, ability to do the ritual unlock on others, magic materialization, divination, barrier powers, mind reading, telekinesis, unique capabilities, etc) and a life link between a haikaishin is established. As a added bonus (or curse), every subsequent potara fusion shall now be permanent instead of being a temporary one hour thing. It can only be undone by a wish from the dragon balls. Instantaneous memorization or instinctual grasping of the natural world (time travel, space exploration, ki mechanics, magic, science, how dragon balls work, giving saiyans SSJ4) is given to the new supreme kai. However it is now expected for the human to cater and help create new life and planets, live on the world of the supreme kai's in otherworld, watch over the entire universe, maintaining a high mortal level, don't die unnecessarily (which kills the destroyer and makes the angel unconscious) and assist when cataclysmic activities are threatening the entire universe. They are above everyone in the entire universe with only the hakaishin and angel being their equals with the Grand Priest and Zeno being the sole superiors. Uniquely the human supreme kai will now have pointy ears like a elf and have pure white, glowing eyes, signs of his newly found divinity. The aura also burns brighter like a flame, but is either still pure white or invisible to non godly ki sensors.

[Note]: Besides the standard uniform, the human supreme kai is allowed to wear three unique other sets of official clothing. The first is a simple martial arts gi used for training and sports competitions. A straw hat along with a cape can be worn as accessories. The second is for godly ceremonial duties, and is akin to the metamorese style of clothing complete with a total face mask. The final however is simply a dark robe that covers all features, but a basic fighting attire is underneath as the kanji for "supreme kai" is stamped on the back of the cloak.

8. Fusion - Not necessarily a transformation, but still a perfect way for humans to get a power up.

- Fusion Dance: Most obvious choice for normal humans to learn.

- Potara Earrings: If a human has both earrings, a powerful hour long fusion can occur. However if a single participant is a supreme kai, it will last forever.

- Ex Fusion: The artificial fusion dance achievable through science.

- Merge: The two beings simply fuse in a flash of light, similar to the Beenz brothers from the Tree of Might or Abo and Kado. Gotenks from DBM is another good example.

9. Hybrids - Being the descendants of either saiyans (like Gohan) or the Three-Eyed Clan (like Tien) will grant the child greater potential and more unique powers. Thus forms such as Great Ape, Super Saiyan, and many others will become attainable.

10. Eternal Dragon - Either make a wish from Shenron to have a transformation or fuse with him just like Goku in GT. The latter might grant a unique form of its own.

11. Technology - Depending on the level of technology available, this may or may not be a exceptional boost. For example, if Bulma can create a saiyaman watch that houses helolite armor inside, the human would become a immediate force to be reckoned with. However if he is simply riding a giant mech, the chances of victory against stronger foes diminishes (unless it is somehow Dr. Wheelo's body or made by Gero). Also if fused with the Big Gete Star, said human can become vastly more powerful while being able to create armored clones.

12. Spirit Bomb Infused - A brief power up where the human absorbs the entire spirit bomb.

13. Ultra Instinct - Perhaps similar to Goku's version, humans might attain a transformation that allows full access to the powers of ultra instinct.

14. Godly Ki - By either becoming a deity, a selected candidate for a destroyer, undergoing unique rituals, or training underneath a god, humans can use a brief power up that transcends normal ki. Perhaps akin to Toppo, some humans might even gain a transformation of their own upon usage.

15. Body Change - Just like Captain Ginyu, keep on switching bodies as a way of powering up. Besides the technique, usage of the Super Dragon Balls can be a alternative method.

16. Miscellaneous - Weird occurrences and intakes such as drugs, curses, fierce emotions (like rage), becoming "Guardian" (like Kami or Dende), sorcerer, absorption (if possible like via magic), undead (becoming a lich or vampire), possession (like Baby), or Turles's Fruit if the Tree of Might can make human beings stronger depending on dosage and the exact circumstances.

17. Jinchuriki - Human magically has a beast sealed inside of them and can harness its power. Tapion from DBM and Goku from Evolution are prime examples.

18. Energy Absorption-induced Super Mode - Instead of firing ki blasts, the user absorbs their blast and channels the ki throughout their bodies. For example, while charging a kamehameha, upon saying the final "HA", the blue energy wave reenters the users body and powers them up temporarily in a explosive manner, though incredibly brief.

19. Genetic Engineering - Human beings successfully implant foreign DNA into their design to achieve greater power and potential forms, akin to Android 21, a different version of a bio-android compared to Perfect Cell. So the absorption of one DNA (like saiyans) can grant the user super saiyan. But the insertion of multiple DNA's will grant the user a unique form, again like Android 21. The dragon Balls is a alternative method to achieve besides through acts of science.

20. Advanced Training - If presented with unique training facilities, the human race can grow stronger with certain masters guidance. The teachings of Krillin, Tien, Goten and Trunks [Gotenks], Korin, Mister Popo/Kami, Chronoa, Jaco/Galactic King, King Kai, Grand Kai, Shin/Elder Kai, Whis, Grand Priest, and many others can pull humanity far, or at the very least a few select individuals. However schools by King Chappa or Mr. Satan may be ineffective in the grand scheme of things, so choose your master (s) wisely. While gone, the teaching philosophies of Master Mutaito, Master Roshi, Master Shen, Grandpa Gohan, Piccolo, Future Trunks, Vegeta, and Goku thrive on.

- Training Schools: Area's to grow stronger at. Places such as Krillin's New Turtle School, Tien's New Crane School, Goten and Trunks Kikoukenjutsu Sword School, Korin's Tower, and Kami's Lookout on Earth is available depending on current skill levels. Special schools are available for specialized jobs such as the Time Patrol in Conton/Tokitoki Cities [Note: Additional masters such as Frieza, Cell. Buuhan, Hit, and Zamasu may teach] or the Galactic Patrol in outer space. However for more advanced fighters, places in Otherworld includes King Kai's Planet at the end of Snake Way, Grand Kai's Planet, World of the Supreme Kai's, Beerus Planet, and Zeno's Palace. However the possibility that "Evil" human beings establishing their own private training schools to cater to individuals based on their ideology will occur. Examples being a reincarnated human (born from a evil namekian) creating a demon clan, engineers and cyborgs being in a Dr. Gero-esque lab for world domination, majinized henchmen working underneath a wizard, superpowered slaves to a demon god, and fusions born underneath dark magic such as the Dark Potara Earrings joining together for a sick cause.

- Core Class: Fundamentally human beings are either martial artists (fighters and sword users), spiritualists (ki specialists), or engineers. It is imperative that a human masters all three to become as strong as humanely possible.

And many more potential power ups for human beings is possible.

And as a heads up, but even without any transformations or power ups, long as human beings have substantial willpower, wits, and teamwork capabilities they can always get stronger. Teachings such as Gohan's Groundbreaking science book and various ki, meditation, and training ritual guidelines are fundamental to all humans. In addition to knowing various techniques and being able to handle some technology, items such as the power pole, bansho fan, senzu beans, and nimbus clouds will be great assists for them.

My Choices:

If I can only choose 5 out of the 20+ options, as a regular human starting out I would go with Advanced Training, Kaio-ken, Unlocked Potential (Mystic Form variant), Supreme Kai, and Spirit Bomb Infused. First and foremost the Advanced Training will become the foundation of what kind of person and warrior you will be. Physical, mental, spiritual, and emotional training will be fundamental in how you interact with the world or what foes you may face, not including your own morality perspectives. So mastering most of the arts on Earth will prepare you for most opponents. Personally I will join the Kikoukenjutsu Sword School and learn swordsmanship with my specialties being kendo and Iaido. Infusing my ki with my zanpakuto [fancy term for katana], I will live by the Bushido codes and be a student of Confucian, Lao Tzu, Sun Tzu, Shinto, Zen Buddhism, Robert Greene (48 Laws of Powers), Taoism, Christianity, and Gohan who lives, sleeps, and dies by the sword. My mind will be well disciplined and have fine control over earthly pleasures as I constantly hone my power capabilities. Hopefully little to no evil will exist in my heart, but if so then I will try my hardest to not allow the evil to consume me. I will choose to live in the dojo and assist my masters and fellow comrades in defeating whatever danger the Earth faces. Upon completing my studies and mastering both ki and swordsmanship, I will depart on good terms and join the New Turtle School. Here I will become more competent in hand to hand combat and have better refinery on ki control to help create my own unique techniques. At this point I will feel confident that Frieza's weakest henchmen will be no match for me. And underneath Krillin's tutelage I hope to become more open to others and have even more allies. I'll also learn the kaio-ken and spirit bomb here, and hopefully master their use in perfect synchronization. But upon training underneath Korin, Kami, and King Kai in Otherworld, I will refine both techniques though whether I have any evil will dictate my spirit bomb's usages. But access to the Zen Kaio-ken will be a personal signature move of mine with multiplications up to 100X being a dream come true.

When the time comes, having my potential unlocked (hopefully it akin to Gohan's own) by Old Kai would be lit. I will take the "permanent" route and immediately become a supreme kai disciple. And surviving the trials of selection will guarantee me being pure of heart, thus granting me the spirit bomb option at last if I became evil somewhere within my heart. And eventually I too shall become the Supreme Kai of the entire universe, thus automatically granting me both godly ki and potara fusion. This alone will boast me to uncharted levels and become a true force to be reckoned with. The "Super Mystic" form will also become available to me, my ultimate form. And as a important figure on the pecking order, I can finally make real changes to the universe though it will not be easy. Though to be fair on the Sacred World of the Kai's, it will look exactly like it does in canon, but I will reside on a Lookout-like structure that hovers over Z-Sword plateau. The lookout will have a amazing palace in a temple-like format, with many retainers, caretakers, spiritualist monks, and comrades living inside. I will solely have a throne room and have a military styled plan room adjacent to it. The whole planet will be populated with loyalists with a powerful sub-base on a lone island will be used when not on the Lookout. A waterfall mountain and various oceans will to be used by me for military reasons. Aspects of jediism and gokuism will be incorporated into my teachings to mortals as I solely fight for the forces of good. Uniquely just like Popo and Whis for Dende and Beerus respectively, I too shall have a personal assistant who hopefully is a majin with a genie absorbed.

Evil kind and demon world demons will be my greatest targets as I improve the overall mortals level significantly. All mortals, immortals, and demon gods who practice evil will either be rehabilitated or vanquished into oblivion. Hell will be the final resting place for those who cannot truly die, but will have their powers permanently separated from them. Whatever race or planet houses dragon balls will be another top priority to protect. They can make changes for the better. Everything else will fall into place.

And if possible but powers such as Eternal Dragon, Ultra Instinct, and Miscellaneous (specifically feelings emotions such as fierce rage) would be neat to possess too. But since being a Supreme Kai grants me two additional power ups (potara fusion and godly ki), I am not complaining if my 5 choice characters was somehow the limit for humans to possess in totality. But If I ever perform my first ever permanent fusion as a supreme kai, I want my fusee (either human, fellow kaioshin, or saiyan) to have all three of these traits.

Do you know "Tales of Demons and Gods"? Martial artists can become stronger by assimilating a demon spirit and become a Demon Spiritualist, acquiring the chance to become a Legend rank (highest normal mortal) or even divine.  I think there are more than one wolf spirit... 
Or another idea, like in "God of High-school" with it's principle of "borrowed power", where an old entity lends you his power by contract or bloodline. 

I think it would help if they established more about what godly ki is.

If it is indeed completely separate and has you on a "base" power level then god ki could very easily be a powerup for humans since their diminutive regular ki is so far gone its impossible to catch up unless you're a mutant freak like Frieza who has so much regular ki he's on the same level as god ki users like Goku or Vegeta. So if you gave Krillin god ki, and this increased him to say brand new SSG Goku levels on the sheer basis of god ki alone then that's all you need. Thinking on the lines of those discarded forms Goku and Vegeta had in the RoF movie, the Saiyan Beyond God or whatever where it looked like their base form just with a different color aura than their usual.

I'm pretty iffy on actual physical transformations for humans so god ki or something like Ultra Instinct would be what I'd prefer, since aside from Goku (where its an actual transformation for some ungodly reason) all UI is about is simply being perfectly in tune with yourself. But given that Krillin and Yamcha are retired only Tien would really qualify for getting a further powerup and he should already be there or at least be close given his third eye.

...But that would require caring about Tien anyway.