>>14988226
By free I assume that piratable stuff counts too, so have a some quick list of good shit.
>fps
AssaultCube, not sure if it's still populated but few years ago it was a blast to play.
Doom 2 through Zandronum and Zdaemon you just need doom2.wad that you can grab from here, inside wads.zip https://mega.nz/#F!AFUBAYqS!vbipx7ds6IY_CHdQn4eOPQ also if you are on wangblows then instead of doomseeker use the doom explorer, it's just a lot better.
UT99 + community patch v451 [patch it to v436 beforehand] + DX10 renderer from kentie.net and/or DX9/OGL2.x renderers from cwdohnal.com/utglr/ OR XOpenGL ogl3/ogl4 renderer from epic forums, still a lot of servers and folks that do play, still a blast.
Ye olde Build and Shoot Ace of Spades, the free version 0.75 is quite populated but you will run into aimbotters at servers occasionally, however at big servers it's not an issue as there are hotpockets that jump in if you use report command against an obvious aimer.
>rts
Classy C&C 95, Red Alert 1, Red Alert 2, Tiberian Sun + standalone mods that you can play at crowded CNCNet, works pretty much with any pirated version and you get like 200+ people at RA1 lobby/100~150 people at RA2 lobby.
Fucking this >>14997042
THE OG AoE2 + Conquerors expansion + Userpatch at Voobly that motherfucking place got like 1000~4000 online players at aoe2 lobbies at any time or Gameranger.
None of that broken steam AoE2HD bullshit.
>turn based
Motherfucking Heroes of Might & Magic 3 Gold/Platinum edition Just torrent the 2 CDs ISO image + ruski HD free patch that adds support for high resolutions/multiscreen setups and other cool features, shitton of players for it at Gameranger.
Battle for Wesnoth, good, free as in freedumbz, with some players around.
Freeciv :^)