Team Fortress 2
Valve’s iconic class-based free-to-play first-person shooter! Source: https://www.freetogame.com/open/team-fortress-2
lootdropdaily
lootdropdaily Dark Orbit Reloaded
A browser-based 3D space-combat MMO with a massive playerbase! Source: https://www.freetogame.com/open/darkorbit
RuneScape
A popular 3D browser MMORPG boasting a huge player base and 15 years of content....