Clans adds a command-based land claiming and protection system to Forge servers. It is a server-side only mod, so players do not have to install the mod to join your server and use it. See the CurseForge page for more details.
This mod can be used with Grand Economy to charge players for creating a clan or claiming land.
This mod is available under GPLv3. You are allowed to include it into mod packs of any kind, without asking for permission.