DuckvileSMP is a small SMP that is inspired by Hermitcraft and it is on Java 1.21.11 with plugins.
The goal is to have fun and not deal with people griefing your base. It has claims plus homes and TPA so moving around feels easy.
You can build towns and cities with houses and big bases. There is Simple Voice Chat so you can talk with friends while you play.
It is not running 24 7 but you can start the server by joining the Discord. The community is meant to be respectful and there are frequent events. It is capped at 15 players online at once and it is on a paid host.

