I found A Game of Cubes and it feels like a survival SMP made for people who like testing Minecraft systems. It started as a private world for family and friends and now it is open to anyone who wants to explore.
The main vibe is no hand holding. You are supposed to learn by exploring and experimenting. The server owner is into emergent gameplay and player driven stuff like in sandbox MMO games.
It runs survival RPG gameplay with MMOCore plus quests and progression. There is Towny for claims and towns and capture sites and campfires. It also has an economy and trade system.
You will run into custom mobs and bosses that scale with the world. Simple Voice Chat is enabled too. Voting can get you free skins and in game prizes.
The core rule is zero pay to win. Everyone starts equal and nothing is sold that gives you an advantage.
