World Utils Mod (1.12.2), includes useful commands and tools for manipulating Minecraft worlds in-game.
World Utils Mod – 1.12.2 – Manipulate The World in Certain Ways
Some of the commands include:
- Remove duplicated entities.
- Remove scheduled tile ticks.
- Replace blocks with another block (or with air, which of course is also a block) in the entire world.
- A setblock command, which (only) works in unloaded chunks.
- An inspectblock command, which shows block and TileEntity NBT data currently saved in the chunk data on disk
- Remove all entities by name from the world files.
- Remove all tile entities by name from the world files.
- Rename entities.
- Rename tile entities.
- Remove non-existing block entries from the block ID map (= clean-up after removing a mod)
- Allows changing entire chunks in the world, or just importing biomes from a different world. The alternate worlds that are used as the source are stored inside the worldname/alternate_worlds/ directory. The mod also keeps track of all the changes to chunks and stores that “database” in the same directory.