First we have the Age of Squat mod. This is an old and discontinued mod. A true gold mine for the more advanced modders.
Most of the models lack code, and animation. I have made it possible to test the mod with preview and buildable models. So you can see what the mod contains. Mod was originally released by Palii. Check the readme in the mod for the original authors description and comments.
Legion of the Dammed
Next we have a ton off new models, vehicles and a re-skinned clone race from the Space marine Legion of the Dammed chapter. Mainly closer to Codex models. Some FX. Some come with their own mod to test them out. All this is meant for modders, and not for casual players.