Hydra SMP is a new survival SMP that is trying to stay small so it feels fun and not overwhelming. It starts with just a few people so you can actually get to know everyone and make friends.
The server plans to become semi private once the member count gets to around 15. After that it sounds like they will slow down on letting new people in so the community stays tight.
Rules exist but they are not super strict. Just make sure you know them before you play since breaking rules can lead to a ban.
Hydra SMP Small Semi Private Survival
casual multiplayer survivalchill survival playCommunity-Driven RulesLimited member capsmall group survival
GG.MINEWIND.NET New Server IPChill Whitelisted Vanilla SMP 1.21.3

I found a whitelisted vanilla survival server on 1.21.3 that is meant to be chill and small community. It has a relaxed casual vibe and it is trying to feel like a real SMP home.
It stays mostly vanilla with a few tiny quality of life plugins. The rules are light and the big one is do not grief builds. PvP is allowed and it is treated as fair game.
The world border is set to 10k for now. All ages are welcome and they may add features later if the community suggests it.
GG.MINEWIND.NET New Server IPGlowySMP Whitelist Semi Vanilla Economy

GlowySMP is a new semi vanilla whitelisted SMP that feels like a small friendly survival world.
There is an economy system so players can earn and spend money. People can set up player warps and build their own shops. There are land claims so your builds stay safe.
The server also has community events plus things like PyroFishing and jobs. There is a separate resource world and stuff like mobcatchers crates and ranks.
From what I see the community seems really welcoming and they are looking for more players to join the adventure.
GG.MINEWIND.NET New Server IP
