Bukkit is a Minecraft server modification software and API, and while the original project itself is stale, forks like PaperMC and Spigot are actively maintained, and most plugins and servers use some variant of Bukkit.
The most widely used, high performance Minecraft server that aims to fix gameplay and mechanics inconsistencies
Fork of Paper which adds regionised multithreading to the dedicated server.
Slimefun 4 - A unique Spigot/Paper plugin that looks and feels like a modpack. We've been giving you backpacks, jetpacks, reactors and much more since 2013.
Voxel world generation modding platform
Citizens - the premier plugin and API for creating server-side NPCs in Minecraft.
PlotSquared - Reinventing the plotworld
A working voice chat in Minecraft!
Capture user input in Minecraft through an anvil GUI in under 20 lines of code
Library for cross-version Minecraft Bukkit support and various efficient API methods.
Immersive and lore friendly enhancements for vanilla Minecraft
You decide what commands players can use or tab complete on your server!
Open-source, multiplatform, and highly customizable minecraft authentication plugin with outstanding features and API.
Crucible, a fork of Thermos, is a CraftBukkit and Forge server implementation for 1.7.10, providing the ability to load both Forge mods and Bukkit plugins alongside each other.
The be-all, end-all of discipline.
Add click and hover events to chat messages!
A Minecraft library for saving, loading, updating, and commenting YAML configuration files
Created by Nathan "Dinnerbone" Adams
Released December 22, 2010