Oh, here's my idea of the Eath Liberation Army:
They have low tech, most of their technology is about the same as our modern one. Beecause of lack of really efficient weapontry to counter other factions, they mostly use guerilla tactics and more more outdated types of warfare tactics.
Firstly, they workers are actually just humans, so they mine much less resources, but on other hand they have special portable transports to store the resources. Plus their workers may learn to cloak and become invisible. Some of their buildings my be cloakable or mobile too.
their infantry is armed with outdated types of guns, like AK47s, M16s and RPG-7s. YOu can also feel here a bit of GLA from C&C referance, that's because I really got inspired by it. thair main infantry has an assault rifle, plus may get molotovs and Medical packs (When used restore a bit of the units health over time). Other their type of units have rocket launchers, which makes tham good against vehciles. They have a special ability to passively give more damage to buildings and probably vehicles and to create Trenches in which infantry can hide. Yes, ELA uses trenches. trenches may use repir on themselves to repair themsleves but stop fighting. You can also use a special Trench ability that destroys the trench but gives back some of your cash you spend on it.
Their vehicles are a M1 Abrams tank and a Combat Buggy. Abrams is the only unit that can actually hold the enemy fire. He has the ability to repair itself but to stop fighting just like a trench, which helps to survive in battle, and ability to passively auto-attack with a machinegun all the surrounding units when ability is on and spends mana evry second when it's on. Abrams damage is quite low, but it has moderate speed and good amount of armor and HP. Combat Buggy is nearly opposite, it has the quite powerful armor piercing machinegun, good speed and low HP, but quite a good range. It's ability is to launch a missle hail in AoE, which makes it useful as hit and run artilery unit, and ability to revel an target area with binoculars, whuch makes it a good scouting unit too.
ELA aircrafts are quite intresting too. Their first aircraft is a non-human controlled invisible scouting aircraft that can ram into hostile aircrafts and demolish them, plus it has no attack and can detect cloacked units. Other one is a heavy helicopter, powerful but slow. But it has the ability to temporary increase the speed of movement and attack, plus it has passive ability to buff surrounding units.
ELA also has quite intresting augmentations for units. Soem of them might be consumeable, they may be dropable and these are more of equipment that some body modifications. Like there may be a camo suit, a night vision googles, a radio pack to communicate with headquarters...
Hope you like my conceot. I'll came up with more idea to it later...