Here's the possible aliens for Omnixes
Group 1)
Diamondhead
Diamondhead's body is composed of an extremely durable organic crystal, making him nearly invulnerable. Diamondhead can control his crystal physiology at will, allowing him to create crude crystal weapons from any part his body on demand or fire crystal shards from his hands. This same ability also allows him to regenerate to an extent, such as regrowing lost limbs. In addition to growing crystal from himself, Diamondhead can grow crystal over other objects. Lasers and other similar weapons are useless against Diamondhead, as his crystal body acts as a prism, refracting the beams. The one drawback to Diamondhead's crystal form is the crystal itself, which can shatter if exposed to sufficiently strong sonic vibrations. While they can regenerate limbs, there is a limit to how much damage they can recover from.
Fourarms
Fourarms is a ten-foot tall, four-armed, four-eyed powerhouse with armored skin and extremely dense musculature, making him unmatched in pure physical strength. His strength is such that he can create shockwaves simply by pounding the ground or clapping all four of his hands together, dubbed the "Big Smack", and his leg strength allows him to cross entire city blocks in a single jump. However, all the extra mass of his muscles and heavy skin makes Fourarms relatively slow, and his size likewise makes using things designed for smaller species difficult, especially when enlarging them is a bad idea. When under the effects of an illness, Fourarms' strength and stamina are somewhat lessened.
Ghostfreak
Ghostfreak outwardly resembles a one-eyed ghost, the result of a second skin, while Ghostfreak's true form, which is seen after Ghostfreak molts, is that of a wraith-like genie with blue claws, decaying skin, and an exposed, upside-down skull with a single eye for a head. Ghostfreak is composed of a variable-density protoplasm which allows him to become invisible and/or intangible at will. Ghostfreak can levitate freely, and he doesn't require oxygen, allowing him to survive in a vacuum. The second skin protects him from Ghostfreak's otherwise fatal aversion to sunlight. The second skin also has 'tracks' on it, in which Ben can move his single eye about, allowing him to see behind him, or anywhere the eye decides to go. In addition to the standard invisibility and intangibility, Ghostfreak can render others intangible through physical contact. His intangibility also enables him to possess humans, controlling them from within. Ghostfreak also has psychic abilities such as telepathy and telekinesis, but the extent of these abilities remains unclear. His true form also has a flock of tentacles protruding from his chest, which can be used as extra appendages. In total darkness, these features become even more pronounced, and he can fire energy blasts from his chest. However, having molted off the protective skin, Ghostfreak is extremely photosensitive, combusting when exposed to direct sunlight over a prolonged period. He is also unable to possess anyone while in alien form, as the Omnitrix repels negative forces aimed at it, but can possess other true aliens.
Grey Matter
Grey Matter is a gray-skinned, frog-like, bipedal alien only five inches tall, however his size belies his intellect, which is second to none. He can create almost anything from spare parts and deduce the function of any device at a glance. This ability extends to organic organisms also, determining the position of nerve clusters under the skin of an alien creature he'd never seen before. His size allows him to squeeze into small spaces, and he can climb walls thanks to tiny suction cups on his skin. He also has sharp teeth, and his slimy skin makes him difficult to grab. However, Grey Matter's size makes him unsuited for battle, and hence you must outsmart his enemies while using the form.
Heatblast
Heatblast is a magma-based lifeform that can control fire at will, either projecting it in a wide range of forms or absorbing it into himself. He can fire streams of flame, create fireballs, manifest tornadoes of flame, utilize said tornadoes to travel short distances, and radiate heat in all directions for a localized explosion. He can also achieve flight by firing at the ground to propel himself like a rocket. Apart from this, Heatblast is also a highly durable alien, able to endure being thrown through buildings without being slowed. While under the influence of an illness, Heatblast's powers are reversed, giving him cryokinetic powers instead of the normal pyrokinesis. Heatblast's dependency on heat is also his weakness, as his powers can be negated by sufficient amounts of water or similar fire-extinguishing materials. His natural body heat also prevents him from handling things without burning them, people included.
Ripjaws
Ripjaws shares a number of traits of Earth aquatic lifeforms—namely alligators, eels, anglerfish, and sharks—combined into a single being. Naturally, his main ability is being able to breathe underwater. Ripjaws can also withstand a remarkable amount of pressure, and his luminescent dangler allows him to see in the darkest of depths (or otherwise dark areas). He can swim at great speeds, and his sharp teeth and claws can pierce through almost anything. His lower jaw can unhinge to allow him to bite much larger objects. Though his tail hides a pair of legs for travel on land, Ripjaws is limited by his need to remain hydrated, dehydrating rapidly if left out of the water for even a few minutes.
Stinkfly
Stinkfly seems to be a combination of various Earth insects (dragonflies, crickets, and praying mantises specifically). His primary ability is flight facilitated by the four thin wings on his back, which grant Stinkfly high mobility and speed. Stinkfly also possesses disproportionate strength, enough to carry people and objects heavier than himself. Stinkfly's four eye stalks give him a wide range of vision from the sky, including the ability to look directly behind himself. Pollen ducts in his eyes and mouth allow Stinkfly to excrete high-pressure streams of liquids. The type of liquid can range from a flammable toxin to an immobilizing jelly. His razor-sharp tail and pincer-like legs can also be used in melee combat. Stinkfly's primary weakness is water, which can negate his flight if it gets on his wings. In addition, while his body is fairly strong, his wings are not. A more minor inconvenience is Stinkfly's intense body odor (hence the name), which is a result of the oils he secretes to keep his joints moving.
Upgrade
Upgrade is composed of nanotechnology, allowing him to reshape his body at will. This makes restraining or harming him difficult, as he can "melt" to avoid either and will quickly regenerate from any damage taken. Upgrade can also merge with other technology, earning his name by upgrading it far beyond its original design as long as he is merged with it. The size of the device is inconsequential. While merged with a device, Upgrade controls it as he would his own body. Even without a machine at hand, Upgrade can reconfigure his form around his eye in order to fire a plasma beam from it. Upgrade is also capable of forming simple constructs from plasma, such as spikes. Upgrade's weakness is his specialization: being technology-oriented, Upgrade cannot possess biological creatures, and sentient or more powerful robots are harder for him to control. Upgrade's liquid-metal composition can also work against him, namely where electrical attacks are concerned. Furthermore, any sort of metal corrosive can upset Upgrade's delicate internal workings and wreak havoc on his systems.
Wildmutt
Wildmutt is a vaguely dog-like alien whose physical features are a cross between a lion and a gorilla. Wildmutt's powerful arms allows him to run, jump, and climb objects at high speeds, in addition to making him fairly strong. Wildmutt has no eyes, but has gills on his neck which allow him to hear and see many times better than humans, giving him radar-like sight which is depicted as functioning somewhat like a thermograph sensor. According to various profiles on Wildmutt, the porcupine-like quills on his back supplement his radar sight and can also serve as weapons, either protecting Wildmutt while he's rolling or as projectiles which can be fired off at will. This ability is unique to adult Wildmutt. Wildmutt's weakness, though it is rarely an issue, is his lack of sight, which can be impeded through various means, and he is rendered effectively useless if his nostrils are clogged. Wildmutt is also the only Omnitrix alien who cannot speak in any understandable fashion, communicating through snarls and growls, which can be a problem when attempting to relay messages or avoid conflict.
XLR8
XLR8 resembles a semi-armored velociraptor, the base creature for the form's design.[21] XLR8 has wheel-shaped feet and wears a helmet with a windshield, which is part of his alien biology, leaving the features of his head unknown. XLR8 can manipulate friction to reach speeds of 500 mph in an instant, and the same power allows him to climb up walls and run on water with relative ease. Using his speed, XLR8 can perform a number of unique feats. He can create tornadoes through centrifugal force, either through running in a small circle or spinning, and can deliver speed-enhanced attacks in rapid succession. Amazing reflexes accompany this speed, allowing XLR8 to quickly dodge attacks with relative ease. His scissor-like claws can also cut through objects. XLR8's weakness is his lack of physical strength, which is about on par with a normal human, although his speed tends to make up for it. Magnets and charged pulses are a problem. They disorient him and cause him to become unbalenced.
