Mercator

It's classic MUD stuff. You pick a class, you grind, and you learn the game the hard way early on. Classes aren't fixed either: a mage can remort into a sorcerer and/or necromancer, a cleric into a prophet or priest, and so on, each branch playing differently. Keep going and you can work toward masterclass content like Death Knight or Archmage, which take a while to reach but aren't just a name change - they come with their own abilities. Outside of leveling there's clans if you want a group to belong to, an arena for PK and duels if you want to fight other players, and quests scattered around for a break from straight grinding. The world is split across a handful of islands. No cash shop, nothing fancy, just a game thats been brought back after a long hiatus.