Bukkit

It's just sponges.

Allow players to get and craft items of power

MultiEnderChest

Stop items from being dropped by a player

A plugin which adds some mechanics which make game harder

Limit the enchants a server will allow

skySMP+ - SkyBlock survival multiplayer implementation.

PvP-FighterZ

Allows players to grow and farm moss and silverfish.

LagFinder

Bedtime 1.2 - Ignore idlers and see who isn't sleeping

Unknown Command

ItemSpawner

Adds Mutton and Horse Meat

Forked version of handcuffs

Certain effects will be given in certain biome temperatures.

HardcoreMode

Easily make ui's that run commands when you click on an item in a gui!

Refill your hotbar slots with items from the inventory

Redstone Walls lets you create controllable walls that can be dynamically any height.