Being an EVO, Rex Salazar can build a variety of machines with his nanites at will. Dubbed as 'builds', Rex's machines can be utilized for transportation or offensive attacks. They are infused with his limbs and add to his enhanced physical condition. Starting off with six original builds, he was granted with the Omega-1 Nanite and gained the ability to build five more.
He could initially operate one machine at a time with minor exceptions; being able to quickly shift between builds. He eventually learned how to employ two builds simultaneously. Unlike the original machines, Rex's Omega-1 machines apply some form of energy-based attacks.
The smack hands are massive orange gauntlets that Rex can transform either arm into (preferably both) to take down larger EVOs. The smack hands give him incredible strength, allowing him to break through obstacles or lift heavy objects. When forming them, he has control over the overall size, length, and flexibility; being able to extend them to reach certain distances. Without the use of his punk busters, Rex can use his smack hands to significantly push himself into the air and ultimately use them to absorb impact when landing. They are also moderately capable of shielding against lasers  and debris,  however, they are weak against acid. Out of all machines, the smack hands seem to be the only ones that are nerve-sensitive.
This mode allows the smack hands to function as high-powered drills and add additional power behind his strikes. However, Rex can use this to easily drill and travel through underground tunnels. Since his smack hands are already sinkable, he used his drills to quickly propel and drag him underwater.
The boogie pack is a jet pack with a pair of wide orange turbine wings. Rex is capable of using it to fly at high speeds; it also gives him a high level of agility. He can launch the twin turbines at an enemy EVO like a bola. He can also shoot two large grappling hooks on the top of both turbines.
The boogie pack can also successfully propel Rex underwater. Rex has also use the turbine wings to create compressed air. Unfortunately, there is a limit as to how much weight his boogie pack can transport at once.
Slam cannonThe slam cannon is a large orange projectile cannon that Rex can transform either arm into. Similar to a rocket launcher, it is positioned to rest on his shoulder. However, it does not produce its own ammo; instead, a maw on the back end of the slam cannon can extend into the ground and reload solid material for ammunition. It then proceeds to fire the balled material at its target with great force.
The Rex ride is an orange hover motorbike that Rex can form out of his lower legs. The vehicle can drive over any terrain and can go over 200 mph. Despite lacking wheels, the Rex ride is capable of driving up vertical loops and curves. It has a retractable battering ram instead of an engine block and it can be used like a shield to break through trees and various other objects. A helmet build also comes with the Rex ride for protection.
The punk busters are a pair of massive orange super boots with retractable spikes on the soles. They allow Rex to jump hundreds of feet into the air or jump across ten square blocks. He can also use the punk busters to repel powerful EVO enemies or kick through thick metal. In his own words, it feels as if "you were roundhouse kicked by a freight train". Like a hydraulic cylinder, the punk busters can have its foot extended to kick enemies away. The punk busters are so strong, a stomp is enough to dismantle its surrounding or cause rising fissures accurate enough to repel its target.
Big fat sword
The big fat sword (also known as the B.F.S.) is a massive orange sword that Rex can transform either arm into. It is one of Rex's most lethal machines. Although it is used offensively to easily cleave through objects, it is can be used to deflect attacks. Once stabbed into the pavement, the big fat sword can provide mobility for Rex and others who hold on to it.
Battle sawUsing a lever on the side of his big fat sword, the top half of the sword will split apart and begin to rotate at a high velocity. This transforms the B.F.S. into the battle saw—a giant orange circular saw that can slice through tough objects. He has used it several times to primarily slice tentacles off from huge EVOs or to cut himself free from tough restraints.
Omega-1 Nanite machines
The blast caster is a machine that consists of a navy-colored, backpack dynamo and a long, black tentacle-like whip that extends from his right arm. It was the first build created with the Omega-1 Nanite. While the blast caster does act as a whip, Rex appears to have control over the appendage like a muscle; wrapping around enemies or managing to grab small objects. When freely flying through the air, Rex can make the whip cut and turn corners at will. Unclear whether this is only possible underwater, Rex has demonstrated taking hold of objects from afar and reeling himself in. It can also channel electrical shocks powerful enough to stun an enemy. The whip can thin out and break if put under enough stress.
The funchucks are the second build created with the Omega-1 Nanite. They are a pair of giant, metallic nunchaku that are attached to both of Rex's arms. He can spin them at windmilling speeds and then launch either arm at his target. Defensively, they can divert heat seeking rockets if spun fast enough. He can also use them to generate a destructive energy pulse by slamming them together after spinning them, allowing him to shoot a light blue arc of energy at his enemies.
Considering its design, the funchucks can be used as a giant lantern in the dark.
Bad axesThe bad axes are the third pair of machines created with the Omega-1 Nanite. They are a pair of large blue axes with energized blades that Rex builds with his hands. The axes are so powerful that they are capable of easily slicing Providence fighter jets with one slice.
The block party is a pair of navy-colored metallic gauntlets that generate blue energy shields made of highly energized atoms. The block party can either generate two individual, circular shaped shields on each gauntlet, or it can form a dome to surround Rex on the ground or in mid-air.
The energy shields are capable of withstanding an extensive amount of damage before shattering like glass. The shields can block, not only energy-type attacks, but ward off solid projectiles and physical attacks as well. If positioned well enough, the shields are capable of deflecting attacks back at the enemy.
Sky slyderThe Sky Slyder is a blue glowing machine that Rex builds with his lower legs. It is similar to a regular surfing board, except it can fly at high speeds in midair. Rex initially had trouble creating the Sky Slyder, but he successfully built it later on.
The Upgrade suit is the form that Rex takes by merging his nanites with one of Ben's aliens, Upgrade. Powered by alien technology, the Upgrade suit enhances Rex's builds and physical condition to levels far beyond technology known to Earth. After being merged with the alien, Rex could withstand more damage and run quicker.
The power fists are upgraded versions of the smack hands. They are alien-tech enhanced machine fists that are much larger and stronger and have retractable spikes, can be fired as projectile missiles and explode on impact. They are far stronger than the original versions, easily knocking back the massive Alpha-Omega with a single hit.
The hyper jet, the upgraded version of the boogie pack, is an alien-tech enhanced machine jet pack. Its speed and maneuverability greatly exceed that of its normal form, allowing Rex to easily avoid a barrage of attacks. Also, as a form of attack it can launch a pair of powerful rockets from the top of its turbines. These rockets pack immense explosive force; a single shot from the hyper jet was strong enough to stun Alpha-Omega and knock him through a large building.
The blast launcher, the upgraded version of the slam cannon, is an alien-tech enhanced machine cannon. Rather than needing to reload ammo in order to be used, the blast launcher produces six extremely powerful heat seeking missiles. 
The alien excalibur, the upgraded version of the big fat sword, is an alien-tech enhanced machine blade. It is considerably larger and more impressive than the normal big fat sword. It place appears to be more energized, granting cutting power much greater than the original big fat sword. It was able to easily cleave through the massive and durable body parts, of Alpha-Omega, in a single slash.
The swift rocket, the upgraded version of the Rex Ride, is an alien-tech enhanced transport vehicle. It is considerably faster than the original Rex Ride, capable of speeds over 1,000 mph.
Full EVO form
A young Rex demonstrated the use of a giant bio-mechanical form that had most of Rex's current builds, including a version of the B.F.S. on one arm, punk busters for legs, slam cannons on both shoulders, and a smack hand on the other arm. It also had a chest plate that slightly resembled the Smack Hands, shoulder pads that resembled the turbines of the Boogie Pack, and the helmet from when he uses the Rex Ride.
While in this large and imposing form, Rex demonstrated typical EVO-on-the-loose behavior, and after reverting to his human form, he lost his memories. Rex partially transformed into this form when he was about to be dissected by Dr. Fell, meaning this may be a defense mechanism. He was also about to return to this form when he was trying to regain his memory with Caesar's ineffective memory machine.
When exploring the underground chambers in Abysus, a colored drawing, presumably made by Rex himself, has some resemblance to this form. There is not any indication that this was inspired by his form, or that the idea of it inspired the form itself.
Full Omega-EVO form
As a complete armor is activated by the Omega-1 Nanite, it is a powerful robotic body. Rex activated the form to defeat the Consortium. It appears that the robotic armor has fiery blue flames as hair and blue colored armor. Unlike his other Full-EVO form, Rex is in control of himself.
Reversal EVO form
When Rex came in contact with Component 326, he transformed into a smaller version of his full EVO form. While he is in this form he has his Smack Hands, a B.F.S. and the Punk Busters. He also has green glowing eyes.
- The Smack Hands were the first machines to appear in the series.
- In FusionFall, the Rex Nano's B.F.S. attack is called "Big Freakin' Sword".
- The blast caster is the only Omega-1 machine to appear in season 1.
- The boogie pack may be a nod to the original M. Rex comic book series, in which Rex voiced his desire to own "a jet pack with twin turbos", like his favorite hero—"Captain Blade Pierce".
- Rex showed enough dexterity with the battle saw to carve a statue of himself from a stalagmite.
- There are a couple of hybrid builds that were not used with the Upgrade suit.
- All the machines Rex builds with the help of Upgrade have a primary black and green striped color scheme.
- Rex tried to create the funchucks several times, but only succeeded when his bio-metrics were up and he needed to save Noah.
- Almost all of Rex's original machines primarily have an orange color scheme. All the new machines have a primarily navy color scheme.
- The change in the color scheme represents that these builds were formed by the Omega-1 Nanite that Rex received from Dr. Rylander.
- Rex's first "double up" was a set containing the Rex ride and the slam cannon.
- For whatever reason, Rex has never used the original and Omega-1 machines together.
- According to Dr. Holiday, Rex loses his builds in a relatively painless way.
- However, he shouts whenever his smack hands undergo pain.
- Most of the original builds seem to have a secondary usage (e.g. combat drill mode, the battle saw, the battering ram on he Rex ride, etc.)
- The Omega builds on the other hand only have a single usage, mostly to make up for their increase in power.
- In Generator Rex: Agent of Providence, Rex can spin the bad axes at an incredible speed, slicing his enemies.
- In the early design, the Sky Slyder was referred to as the Skyslider, Sky Slicer, and Sky Board.
- When Black Knight absorbed a Meta-Nanite her machines were identical to Rex's but with a purple and black color scheme.
- Caesar once theorized that Rex's unique powers might stem from the mechanical Meta-Nanite hidden in his body.