GitHub - EngineHub/WorldEdit: 🗺️ Minecraft map editor and mod

Carpenter's Blocks - This mod adds new blocks such as slants and corners which can be made to look like any other block in the game! Extremely useful for artistic builds. (For 1.12+ see BlockCraftery)

Chisel - This mod adds multiple new textures to lots of blocks in the game, adding a wide variety of textures. (For editing units smaller than blocks see Chisel and Bits.)

FastAsyncWorldEdit

Blazingly fast world manipulation for artists builders and everyone else available for bukkit sponge forge and nukkit x