The species must be smart enough to count as a transformation. Like Wildmutt, Groot definetly is smart enough, but the speech would still be a problem.

AKA Groot.

Flora colossus (Marvel)

This one is kinda obvious, but organic beings like kryptonians are prime candidates for omnitrix transformations.

AKA Superman... AKA Clark Kent.

Kryptonians (DC)

Mr. Ring-A-Ding is an avatar of Lux made of light. It's been deconfirmed that the omnitrix can scan abstract concepts (Such as light) in the form of species.

NOT Lux.

Mr. Ring-A-Ding (Doctor Who)

The Omnitrix has copied other biomechnical organisms before (Like Upgrade, Clockwork or Nanomech), so it could most likely scan a cybertronian.

AKA Optimus Prime or Megatron

Cybertronian (Transformers)

It's possible, should the wearer also have the astro-regulator. But the omnitrix, by itself, wouldn't be able to have TOAA as a transformation, since he lacks DNA of any kind.

The One Above All (Marvel)

DJW actually confirmed the omnitrix has access to dolphin DNA, meaning that the omnitrix can obtain more than one DNA sample from a planet.

Dolphin

In Megaman X6 (Technically also X5), it was stated that reploids like Zero do have a "DNA program" so it's not far off to consider them as a transformation.

AKA Megaman X or Zero.

Reploid (Megaman)

Transformations like Upgrade (Made of nanites) or Nanomech (Human-nanochip hybrid) are more so incomplete forms. Turning into a full on single nanite doesn't seem possible.

Nanites (Generator Rex)

The omnitrix has certain failsafes that do not allow it to scan mutant DNA for safety meassures. It hasn't been confirmed if these failsafes can be turned off.

Could also apply for other mutants from the series like OV Phil or Clancy.

Kevin 11 mutation (Ben 10)

Mewtwo is just a clone of Mew, so it's possible. The pokedex even states the two are different species despite Mewtwo being one of a kind (Lore-wise).

Mewtwo (Pokemon)

Frieza (Also King Cold) is a mutant. While characters from his race like Cooler are possible transformations, should Ben scan Frieza, he would just get a regular member of his species.

Frieza (Dragonball)

Malware's a mutated galvanic mechamorph, so no.

Malware (Ben 10)

Unlike Cybertronians or Reploids, Butter Robot is a much simpler machine without much sapiens or DNA.

Butter Robot (Rick and Morty)

Although sapient, it's still brought to life by magic alone without DNA.

Magic carpet (Aladdin)

Extremely debatible. Anodites are made entirely of magic without much in the way of actual DNA. Hybrid descendants born with "the spark" are usually more so connected by parentage than biology.

AKA Verdona or Sunny

Anodite (Ben 10)

We know thanks to Albedo that a human transformation is accesible, should the wearer just not be human.

Finally! Some Us representation!

Human (Us)

Mutated to'kustar. Also seem to have their sapiens below the average to'kustar, to the point of forgetting how to speak.

Way bad (Ben 10)

Should the user not be human, the genetic difference is enough to where it might actually count.

AKA Flash. Also applicable to other metahumans.

Speedster (DC)

Derrick J. Wyatt has confirmed that there is a setting that allows the user to turn into the opposite sex that Ben hasn't unlocked yet.

(Because why not.)

The opposite sex.

Reapers are more of a transformation for humans that's given. It'll be like having a transformation for ultimate forms be separate.

AKA Sho or Kitaniji.

Reapers (The world ends with you)

Obviously, but stuff that isn't a basic skill for them like the kamehameha or transformations wouldn't be instantly accesible.

AKA Goku or Vegeta.

Saiyan (Dragonball)

Another clear choice, but the omnitrix transformation should come with a backpack equipped, similar to NRG's containment suit.

Irken (Invader Zim)

According to DJW, slimebiots do not have genetic material equivalent enough to DNA that can be stored.

AKA Skurd.

Slimebiot (Ben 10)

Chaos comes from a mutated chao. The ancients from Frontiers might be listed in the omnitrix tho.

Chaos (Sonic)

King Kong has shown human level intelligence, so he's sapient enough to qualify as a transformation.

King Kong (Monsterverse)

Demons in Megaten are usually brought to life by code and black magic. They are just avatars of mythological figures shapen into life thanks to magnetite, rather than the real thing.

AKA Jack Frost, Pixie, etc. For the sake of clarity, we're talking about the demons' depiction in SMT 1

Demons (Megami Tensei)

It's been stated that eating a devil fruit changes your lineage factor (DNA in OP terms), so it could be a case similar to speedster where it could pass as a transformation.

AKA Luffy, Smoker, Chopper, etc.

Devil fruit user (One piece)

It's been said that they can't reproduce normally, so they probably lack DNA to pass as a transformation.

AKA Ryuk.

Shinigami (Death note)

They're sapient enough to qualify, but it would just be the symbiote itself without a host, probably.

AKA Venom or Carnage.

Symbiote (Marvel)

AKA Zoidberg.

Decapodians (Futurama)

Could Ben 10 turn into a saiyan from Dragonball? How about a pokemon? That's what this quiz is about. A truth or false centered quiz, pointing out which of these beings the omnitrix could turn it's wearer should it be avalible to them.

3 key hints (or rules) to qualify as a transformation are:
-They need to have a certain level of sapiensce.
-They must have "DNA"
-Depending on the user, the transformation must be different enough from the host.

If I made any mistakes, please let me know. More research is always appreciated.

Also, just in case, SPOILERS will be everywhere, so if you see a creature you don't recognize, tap out if you don't feel safe.