Bukkit

Adds a much needed aspect to combat from horseback.

SQLLibrary

Give a player hearts when he kills someone

Get sponges by right clicking yellow wool with a stick (Configurable!)

Launch Pads

Destroy arrows shot by dispensers / mobs

An API for creating shops.

Pay4Tp

Allows players to instantly drink potions.

DragonConsole, This plugin allows you to type as you would in a server but in the cmd / console!

PlayerNoGhosts

Flyboy

SpoutItems will let you change an item's appearance, using Spout.

Set Cake

Whip Your Players Into Shape With This Easy To Use Light Weight Plugin!

A plugin for detecting and removing redstone clocks automatically/manually.

Disables sponges sucking up water.

Bukkit plugin allowing use of commands to play sounds and effects.

Force players to have a certain item in their hand to use a command

Diamonds used as weapon do damage and can capture the creatures soul as SpawnEgg or as ore-creating pickaxe.