Planetary Annihilation, Warcraft 3 (at least pre-reforged if you can get a hold of an old copy), Unreal Tournament, Killing Floor, Battle for Middle Earth (1 & 2), OpenTTD, Simutrans, Settlers: Heritage of Kings, some of the older Wolfenstien games, Battle for Wesnoth, Warzone 2100, Teeworlds, Widelands
A handful - lemmy.world because I found it first, feddit.nu because it’s Swedish, piefed because it seemed interesting, dbzero because of yarr and foss