Bukkit

automatic move crafts from MoveCraft

Server speed and interface improvements

Minecart Mania extends Minecrafts minecarts, fixing bugs, adding vast customizability, and admin management features.

Minecraft version of the Hunger Games

NoDropEmpire

XCon v0.5a

makes Minecraft SMP a lot harder

The popular Arma 2/3 mission brought to Minecraft

DragonTravel - The CitizensNPC addon to DragonTravel

mcRadio

MCHorde

IceSpeedWay

The ultimate zombie experience, bringing hell to a server near you!

CreeperAppleCheatEazy

Simple mob spawn config with advanced customization

EchoPetMenu

Create a door that you and only you can open, and cant be destroyed (or the blocks around it)

Add Radiation To Your World

Warzone

MOCDreamCrafter