Massively multiplayer games rapidly calcified around a specific set of design ideas (eg. World Of Warcraft) and so many other attempts to jam a load of players onto a single server quickly disappeared (eg. most games by Improbable or Amazon).
Foxhole is one of the few to do it successfully: a single, massive World War 2 battlefield in which players don't just fight at the frontlines, but form supply routes, build defenses, and otherwise take the reigns of the logistics of war. After five years in early access, Foxhole released version 1.0 today.