Spreadrooms

Once started, the rooms expand across the world and consume the blocks they reach, so a player who stays on the spreading edge will see the world gradually replaced. The mod creates a world border of 200 blocks by default, which is configurable and centered on the player who runs the spreadrooms start command, and the spread begins from the southeast corner of the border. Spread timing, variation, room size and generation are all set through the mod's configuration, so a server owner can change what blocks the rooms use and how quickly they grow.

Only the server needs Spreadrooms, since it adds no new blocks, items or entities. Players join without installing anything. Because the spread can cause heavy performance impact, the author suggests letting the rooms generate for a while before players start playing. The mod cannot be turned off once started. Files are published for Fabric only, for game version 26.2, and the code is open source under the CC0 1.0 Universal license.