MCEdit has been discontinued. Similar games include Litematica, which is free and open source. Other options are Amulet Map Editor, WorldPainter, Schematica - Minecraft MOD and MCA Selector. In total there are seven games like MCEdit for Mac, Windows and Linux.
Litematica is a client-side schematic mod for Minecraft, with also lots of extra functionality especially for creative mode (such as schematic pasting, area cloning, moving, filling, deletion).
The Amulet Map Editor is a new and innovative Minecraft map editor made by the Amulet Team, a team formed by the contributors that brought you MCEdit-Unified.
United States
WorldPainter is an interactive map generator for Minecraft. It allows you to "paint" landscapes using similar tools as a regular paint program. Sculpt and mould the terrain, paint materials, trees, snow and ice, etc. onto it, and much more.
Netherlands
EU
With this mod you're able to display a ghost image of a schematic file inside Minecraft to rebuild a structure or export any part of your world (or a server's world) into a schematic file. You're able to export parts of your world, too!.
United States
GermanyEU
WorldEdit is an easy-to-use in-game Minecraft map editor. Through a combination of commands and "brushes," you can sculpt your world or simply perform numerous terraforming tasks.
NBTExplorer is an open-source NBT editor for all common sources of NBT data. It's mainly intended for editing & viewing Minecraft game data.
United States
