What happened to other 3D Maid Marian Games?

Sadly, all of Maid Marian games except Sherwood Dungeon were discontinued since the plugin they required to run in player browser's is no longer supported. Sherwood is still playable nowadays, as you mentioned, but unfortunately it lacks maintenance and updates. However, the community is still present in the game, interacting between them and role playing as it's possible to preserve the game fun. Essentially, Sherwood is nowadays a community-focused game, most likely a place where people go to chat and make new friends. I hope I've answered you.