What RTS games do people still play online?

I'm curios, outside of Starcraft 2 and Grey Goo, what other RTS games of the type do people still play online? I only mean games of that type, not Total War style games or Turn based games.

Since Gamespy died alot of games went offline, and while fan made solutions are available for some of them, it's hard to actually find anyone using them.

Depends a bit on where you set your lower limit. I sometimes see people claiming anything with less than a thousand concurrent players is a dead game.

I usually see 2-3 open lobbies in SunAge whenever I check out it's multiplayer, and the Age of Empires, Age of Mythology and Rise of Nations games on Steam seem to have somewhat active multiplayer communities too. The open source RTS Evolution RTS, which is also on Steam, regularly hosts multiplayer events where they get lots of participants, and there's the older open source RTS Warzone 2100 which maybe has 1-2 matches going on at any time.

Starcraft: Brood War. Only game you'll ever need.

Brood War is probably the best multiplayer game ever, but its playerbase is almost as small as SC2's at this point, a shame. Maybe Company of Heroes 2? I have no idea to be honest, though Supreme Commander: Forged Alliance is probably worth looking into since it's one of the few that might be interesting for more than a handful of games.

I'm assuming people still play Total Annihilation.

Warcraft 3 spawned that infernal piece of shit called DoTA and shall not be spoken of in the sacred realm of RTS.

Age of Empires 2