Bukkit

Scriptable, interactive citizens.

Required by Custom Items 11.9 and earlier

PerWorldPlugins allows plugins to be set to hook onto certain worlds using the config.

Make any recipes through GUI's only - the only plugin that supports itemmeta, like enchantments - The most powerful crafting plugin.

A bukkit plugin for adding neural networks into minecraft.

OfflineManager - Manage offline players with commands!

RaspberryJuice

A fast cross-version particle API for Spigot and Bukkit server.

API for changing player nametags

Utils and APIs: Config, Language and Inventory API, Protection Utils: WorldGuard, LWC, PlotSquared

Create custom recipes Crafting Tables, Furnaces, Smithing Tables, and more. Support for NBT and more

BarAPI

Extend Minecraft using Javascript

Better command management !

MachinaCraft

This does nothing on it's own and is a requirement for some of Tux2's plugins.

An inventory framework for managing GUIs

A custom shop for spawners in a GUI

Use flint to edit armor stand attributes without commands

Your own Custom Mobs with everything you like