Bukkit

Heads is plugin wich allows you to set steve skull to other player's head!

DisplayTags

Anti Proxy

Use MrVanish to make it look as though you left the game!

Minecraft plugin to help moderate a server

GlobalPlugins enables server owners to load 1 plugin over multiple servers

Ender Eye Changer

A basic plugin that adds essential functionality (oh and spleef :D)

Prevent some blocks and/or items to be placed.

GhostMode - fly through blocks!

MineCarts

InactivityManager

The Enchant Box

Adds grenades to your server.

LoginPlayerPriority

MTP Plugin-CmB

Add Game Info in to Your ActionBar

SpamExclude

Fake banning, login, etc., compressors, and change client-side time!

Create a custom account or link real MC accounts and switch between them.