C&C Red Alert 3: Soviets: Units

Infantry

Conscript: Conscripts are the workhorses of the Soviet army. The lowest of the low, they are grunts armed with basic weaponry. They are most effective in groups due to their limited firepower.
Secondary ability: Molotov Cocktails: Conscripts can switch to throwing this explosive concoction at enemy targets. It is particularly effective at arching over the protective shields of Allied Peacekeepers.

Combat Engineer: Combat Engineers serve the functions of all Engineers in C&C 3: they can capture enemy buildings, repair friendly ones, and capture neutral structures. The Soviet Engineers carry a very small pistol which is mainly suited to killing other Engineers.
Secondary ability: Battle Bunker: The Engineer can construct a small battle bunker on the battlefield that infantry can use for shelter.

War Bear: The Soviets answer to an enemy unit is generally to utilize one of their own that is bigger, stronger, and louder. So is the case with the War Bear, the answer to the Allies' Attack Dog. Like the dog, the War Bear excels at killing enemy infantry.
Secondary ability: Roar: The War Bear can emit a loud and fearsome roar on the battlefield, stunning nearby infantry.

Flak Trooper: Flak Troopers saw combat in Red Alert 2, and are back again for this fight. Carrying a shoulder-mounted Flak weapon, they can fire explosive ordnance at enemy infantry (for best results, aim at groups of infantry) and aircraft.
Secondary ability: Magnetic Mines: Flak Troopers can plant mines on the battlefield that stick to and slowly damage enemy vehicles.

Tesla Troopers: Another old friend, Tesla Troopers carry a portable Tesla weapon with them on the battlefield capable of frying enemy vehicles and infantry alike. As in Red Alert 2, they can power friendly Tesla Coils in the event of a power outage.
Secondary ability: EM Disruption: Tesla Troops can, using their specialized weapon, emit a small EM wave that briefly disables nearby enemy vehicles.

Natasha: Natasha is a Soviet Commando par excellance. Armed with a high-powered sniper rifle, she can shred enemy infantry on the battlefield and use her devastating secondary ability against vehicles.
Secondary ability: Pilot Snipe: Natasha can snipe the pilots of enemy vehicles, allowing friendly troops to commandeer them. 

Vehicles

Terror Drone: Similar to Red Alert 2, Terror Drones can leap inside enemy vehicles and tear them apart from within.
Secondary ability: Electro Stasis Ray: Like the Tesla Trooper, Terror Drones can use an electric weapon to disable enemy vehicles.

Sickle: Similar in appearance to the Terror Drone, the Sickle is instead armed with machine guns, making it most effective against enemy infantry.
Secondary ability: Flea Jump: Utilizing a special leaping mechanism, the Sickle can jump from one level of terrain to the next.

Hammer Tank: The Soviet main battle tank, the Hammer is a typical Soviet tank: heavy, powerful, and slow for its size.
Secondary ability: Leech Beam: A neat weapon, the Leech Beam is capable of ripping the weapons off enemy tanks if it is engaged while they are destroyed. The stolen weapons and then welded to the Hammer for use against the enemy.

V4 Rocket Launcher: The V4 Rocket Launcher is newer form of the older Soviet artillery. Unlike the V2 and V3, the V4's missiles cannot be shot down by enemy anti-aircraft guns.
Secondary ability: Multiple Warheads: The V4 can fire multiple, smaller warheads at once, spreading the damage out over a larger radius.

Bullfrog Transport: The Soviet transport of choice, the Bullfrog is capable of rapidly transporting infantry across the battlefield. It has a powerful Gatling Cannon can shred enemy aircraft.
Secondary ability: Man Cannon: The Bullfrog ejects its passengers not through a simplistic method (doors), but rather through a Man Cannon, which literally shoots the infantry back into the fray.

Apocalypse Tank: The Apocalypse Tank is a powerful weapon capable of ripping through enemy vehicles with its powerful twin cannons.
Secondary ability: Magnetic Harpoon: The Apocalypse Tank can use its Harpoon to drag enemy tanks across the battlefield, where they are converted to scrap to fund the Soviet economy.

Sputnik: Similar to an Outpost from C&C 3, Sputnik, when deployed, increases the ground control allowing Soviet buildings to be placed on new parts of the battlefield.

Ore Collector: Essentially a truck, the Ore Collector carries resources for the Soviets.
Secondary ability: Chobham Armor: Activating this ability increases the unit's armor but reduces its speed.

Ships

Stingray: An amphibious unit, the Stingray is a combination Tesla Tank/Boat capable of frying enemy vehicles, ships, and infantry.
Secondary ability: Tesla Surge: The Stingray can electrify the water underneath it, sending currents out to damage nearby units.

Dreadnought: The Dreadnought is the largest Soviet ship, capable of shelling enemy bases with its powerful missiles.
Secondary ability: Sacrificial Fire: Using this ability, Soviet Dreadnought crews ignore their (already lax) safety protocols, firing missiles as fast as they can, but damaging their ship in the process.

Akula: A powerful Soviet ship-killer the Akula submarine can only fire at enemy naval vessels. Its powerful torpedos do this one job very well, however.
Secondary ability: Ultra torpedos: Removing all guidance systems from the torpedos, these powerful weapons can as a result only go straight ahead, but deal more damage when they hit their target.

Aircraft

Twinblade: Armed with rockets and machine guns, the Twinblade can rain death from above on enemy units. 

Secondary ability: Airlift: The Twinblade can carry moderately-sized vehicles and infantry across the map using this ability.

MiG Fighter: The MiG Fighter fires exclusively at enemy aircraft, but it does that one task very well, shredding through them quickly.
Secondary ability: Return to base: Not special, it just turns around and flies home.

Kirov: A super-blimp, the Kirov carries a great number of bombs which it happily unloads on enemy targets.
Secondary ability: Gastroburners: While these slowly damage the zeppelin, these afterburners enable the Kirov to move much faster.

 

Detailed Faction Information:

 

RA3 Faction Information: