*You gain the ability to use Ki, starting at a level matching that of Son Goku when he fought Raditz (which includes physical fitness so don't worry about that) they can be naturally increased with training. Of course like any skill if you stop training for a significant amount you WILL start to get weaker unless you have another power that can remedy this. You can also teach others how to use Ki.
*Pick ONE race from the Dragon Ball mythos. You now gain all the unique traits and abilities of that race with an optional appearance change to match said race. Meaning for example if you wanted the powers of Freeza's Race but want to remain inconspicuous due to their nonhuman appearance, you can choose to keep your normal look.
*If you pick Namekian you instinctively know how to make your own set of Dragon Balls, which start out as powerful as Earth's set at the start of the series. This can potentially be increased with self-study and spiritual meditation, but it takes a while (months at the very least) to figure out. You can spawn Mutated Namekian offspring (who are innately 100% loyal to you) by spitting up eggs like King Piccolo. You have a measure of control over their appearance and abilities, but they will generally never be able to pass as human unless you have other powers that could potentially influence your appearance or DNA, and by extension theirs. Note that vomiting eggs drains a lot of energy, the amount of which varies depending on how powerful you want to make the resulting offspring, so overdoing it can kill you. You can also spawn regular Namekians if you so choose. All offspring made this way can be classified into either the Dragon Clan or Warrior Clan. The Dragon Clan have healing abilities and can learn to make Dragon Balls like you, whereas the Warrior Clan is a lot more gifted in raw combat ability. You can also permanently fuse with other Namekians (which yes includes your own offspring you monster) to increase your power, but the fusion has to be completely willing for all parties involved.
*If you pick Majin, then like Buu, can absorb the skills and powers of other beings by engulfing them. However this can also warp your personality and appearance depending on the kind of person you've absorbed. This also means you can potentially split into two or more separate Majins if there's a literal internal conflict within you. Like the Namekians you can also asexually reproduce, albeit yours is different because you can literally break off a piece of yourself and make it into a brand new Majin. You can also achieve a 'Pure Majin' transformation that makes you look identical to Kid Buu and grants you has techniques at the cost of also feeling the same madness that engulfed your progenitor. You can learn to control this power and retain your sanity while in this form, but it'll take time and training.
*You know how to build and repair all of the unique technology seen in Dragon Ball such as capsules, hovercars, scouters, spaceships, etc...
*You are an expert in any ONE martial art shown in the series, knowing all of its signature techniques. However only training and live combat experience can push you towards true mastery. Note that a lot of characters blatantly steal techniques from each other so a technique you thought was universal might actually be unique to a school. For example, Ki-based Flight was originally discovered on Earth by Master Shen of the Crane School, but characters who didn't study under him copied it after seeing it in action like Goku. That's not to say you can't learn the techniques of other schools, but you'll have to figure out how they work on your own. A difficult but not impossible task.