(Could a mod or someone rename this topic "Doodstormer's Sketchbook"? Thanks.)
I be working witha programmer/spriter on a Terra RTS. There's going to be three factions, but others will be added via expansion packs (Like any good RTS would

)
Here's some concepts:
New Sol Miner's Alliance

Standard Infantry

Assault/Infiltration Infantry

Rocket Infantry

Resource gatherer/Builder (Yes they're dwarves.)

Flying/Recon Infantry
Aguans
The Aguans will be able to build on water, and all their infantry can swim.

Standard Infantry
Templars

Standard infantry. These suckers can rebuild each other.