In the universe that features Ben 1, the Omnitrix and the other models that followed have the genes of many races that are alien, which the supposed hero utilizes. What this in essence means is that this list will not only have those alien avatars that Ben Tennyson takes on but also the other races that the Omnitrix got DNA from.
We cannot say that this is a complete list or even the topmost of them, but given here is a list of 15 aliens:
Names and Pictures of Ben 10 Aliens
1 Heatblast: This one is Pyronite and is from the star named Pyros. Heatblast The body of Heatblast is made up of a bright inner body that is made of magma and is covered with brown and dark red rocks. He is Ben’s very first transformation and this happens accidentally
2 Wildmutt: He is from Vulpin which is the garbage planet and has a canine appearance with not tail or eyes that can be seen. Without sight Vulpimance makes use of the gills on the neck for thermography echolocation and has other senses like smell and sound. The transformation of Ben to Wildmutt occurred after his experiment with Omnitrix
3 Diamondhead: Diamondhead belongs to the planet named Petropia. Diamondhead can take control of his crystal body to make weapons in crude form or throw shards of fire crystal from the hands. Ben turned into Diamondhead the first time to kill the giant robot from Vilgax.
4 XLR8: Is a Kineceleran from the planet Kinet. He looks like a velociraptor that is partly armored. He has feet that are shaped like wheels, claws that look like scissor and the helmet that has a windshield. Ben turned into XLR8 when he started to fiddle with his newly discovered powers
5 Grey Matter: Is part of the Galvan race which is known for their intelligence and they are known to have created technology like Null Void Projector, Omnitrix, Galvanic Mechamorphs and more. Ben does not like Grey matter due to the diminutive size and he is accessed by chance.
6 Fourarms: He is from Khoros which is a desert palace which has produced a species that is strength oriented. Ben uses the strength of Fourarms to formulate shockwaves by clapping hands together or hitting the ground.
7 Stinkfly: Lepidopterrans happen to possess four eye stalks which gives them vision from all directions and they also can shoot a light blue beams and their mouths can shoot out foul smelling liquids at high pressure. Ben became Stinkfly when he had to rescue Gwen.
8 Ripjaws: The Piscciss Volanns are quite fish like and have the characteristics of fish on earth. They can take a lot of pressure and swim fast and are also known to bite even through steel. Ben transformed into one to grab the eggs for Krakken from Jonah.
9 Upgrade: Is Mechomorph and they can merge totally with technology and can also shoot positronic plasma beams from their eye. Ben became Upgrade to prevent some thieves from robbing an ATM.
10 Ghostfreak: Is from Anur Phateos and these are awful beings with one eye on a reverse skull, having a striped ghost tail and sharp claws. They can also become invisible and fly. They are stronger in dark and weak in light. Ben turned into Ghostfreak to steal out of the home of his great aunt.
11 Cannonbolt: Is an Arburian Pelarota from Arburia. He has broad shoulders that are covered in plating of armor that is nature and they can become into one curled ball like the armadillo and cover him with armor totally. Ben used Cannonball due to a transformation that was accidental.
12 Wildvine: These are aliens that are plant based and have roots for legs and carnivorous plant like flaps on their heads. They can extend limbs and merge with other plants among other abilities. Ben used this form by accident to face the Mycellum
14 Snare-oh: Is a mummy like creature that also work as tentacles and can regenerate when injured. Their weakness is that they can be burned and also vulnerable to getting wet Ben transforms into this form while fighting Yenaldooshi.
15 Frankenstrike: Has the ability to generate electricity and uses it to blast others and also stick himself to surfaces of metal using electromagnetism.