Bukkit

A plugin to warn your players when your server will restart!

The first Anti-Swear plugin that uses Neural Networks.

QuickSell

Gives the ability to cut down trees at once. Just like Timber mod.

Disguise as a mob or other player

a feature-rich world size limiting plugin, which can also generate or trim a world to your border

Schedule configurable server wide broadcasts easily

CoreProtect

Advanced /vanish plugin which makes other players think that you're not on the server

Provides automated plots with protection (MultiWorld support)

Change the colour of the server chat!

BukkitGUI - the most downloaded GUI for bukkit and any other server

Manage Bedwars-Maps automaticly

Expand the capabilities of Skript with skRayFall

PrisonUtils

Lockette v1.4 - Simple chest and door lock, no databases!

If you've ever used the VeinMiner mod for minecraft Forge, it has now been recreated for Bukkit, CraftBukkit, and Spigot

MyCommand

Get slimefun dusts from breaking ores!

Massive Core