OnlineTime is a plugin that only advances time when players are online. It does enabling the gamerule doDaylightCycle whenever a player joins and disabling it whenever there are 0 players. This could be useful for SMPs running 24/7 that want the daytime to accurately reflect how long they've played for.

Commands
- /otreload - Reloads the configuration


Forge/Fabric Port?
This plugin is open source and CC0 so feel free to make your own. I would love to learn about how Forge and Fabric work, so I may even make my own official version!