The Rebel Alliance wield X-Wings and a mighty Heavy Tank that Looks like a Mammoth Tank. If you pick the Galactic Empire expect the Alliance to be the worst foe you will ever fight against.
Infantry
The infantry especially the Plex trooper can stand up to many Imperial Walkers but Rebel Troopers are fewer in number to storm troopers but have more firepower.
Regular Rebel Grunt infantry are especially used to swarm most targets and they got some infiltrator units available.
Rebel Soldier
Standard troopers that can take cover to reduce damage.
Plex Trooper
Elite heavy infantry that can take one even the heaviest Imperial Vehicle.
Infiltrator
Guys that infiltrate bases and has a sniper gun.
Ground units
Rebel T4B Heavy Tanks are the most best ground units they have. Able to stand up to many Imperial Units but also the worst foe the Empire will ever meet.
Spaceships
Rebel ships tend to have weak firepower and armour but their speed is unmatched.
Airspeeder
On land battles Airspeeders are the main air units for the Rebels because they can cover the air and the ground but watch out for specialized walkers that can shoot them down because without them AT-ATs can destroy your ground forces.
X-wing
X-Wings are the worst foes that the Empire will fight against.
Y-Wing
Y-Wings are perfect against all Capital ships and for bombing runs. Tends to hate Imperial Tartan cruisers.
Mon Calamari Cruiser
Mon Calamari Cruisers are the worst foes Star Destroyers will meet in battle(Two Star Destroyers are needed to destroy one Mon Calamari Cruiser). Also hates tie bombers. Also the grand finale of the Rebel Fleet.
Corvettes
The Corellian Corvettes are perfect anti fighter and anti bomber patrol cruisers but have a horrible habit of getting caught into tractor beams of star destroyers especially Princess Leias ship. Also for anti patrol cruiser duty is the Gunship which missiles are good for bombers and patrol cruisers.
Rebel Capital ships tend to hate bombers like Tie Bombers for no reason so keep some X-Wings or Corvettes nearby the Cruisers.
A-Wing
Use A-Wings to do heavy damage to other aircraft but keep in mind they got weak armour.
Marauder Cruiser
Marauder Cruisers are artillery ships which has good firepower but have lousy speed and armour.
Nebulon B Frigate
A notable ship that fills many roles. Once Imperial but also the rebel alliance.
Assault Frigate
This thing fills to many roles and has the ability to transfer all power to shields.
Corellian Gunship
Something Tartan Cruisers hate.
Z-95
A predecessors to the X-Wing and the successor to the ARC-170.
Hero units
They got a few Jedi(Order 66 cause the Rebel Alliance to have less jedi) but Red Squadron is the most worst foe the Imperials will ever meet. Also Ben Kenobi is back from the Clone wars but if he gets into a lightsaber fight with Vader the other units cant help Kenobi in a one on one lightsaber fight.
Home One is available to assist you in space battles any time. His concentrate target ability is quite powerful.
Anakins son Luke is also part of an X-Wing Squadron but latter on a jedi on the ground with Saber throw and force cloak.
The Special version of the Correllian Corvette is used to outrun foes and weaken enemies but Captain Antillies is unavailiable because he was killed by Vader due to star destroyer used its tractor beam to capture his Corvette.
Han Solo and Chewie are also yours to command. The two smugglers had many ways of infiltration like Chewie can capture only one imperial vehicle at a time especially AT-ATs. Their Millennium Falcon tends to have a bad habit on getting into tractor beams and getting captured by Star Destroyers however.
C-3PO and R2 are known to do the following things called steal technology and other various actions.