Amulet Map Editor - 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
MCEdit - MCEdit is an open source world editor for the popular game Minecraft.
Wurst - Minecraft open source hack
LiveSession - LiveSession helps you analyze users’ behavior, improve UX, find JS bugs, and increase conversion rates using session replays, and event-based product analytics.
WorldGuard - Minecraft Plugin - WorldGuard is a powerful plugin with a large bag of tricks for server owners, server map makers, regular survival servers, and everyone in between!
Schematica - Minecraft MOD - 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!