Bukkit

Have some fun with your armor!

Give players hearts!

ctOS Connecting Our World To Hackers

Iron Man

DeathFX will play a cool effect on a player's death

Ice Walker allows for players to walk on water by turning it to ice

MyHospital

KitPvP with special items, 8 different kits and multiple arenas

allows you to enter /gm 1 instead of /gamemode 1 and /gm 1,2,3,0 player

Cart Armor protects against most types of damage

Create and customize fireworks

BookCopier

Allow players to recycle items into preset community chest.

TeamSkyWars Bungee

Play as Jason slaughtering all in your path or as a camp counselor wishing you had picked a different summer job.

PVP_PROPER tracks all PvP interaction so accurate stats and kill-types can be broadcast to the players or used on your website.

CowCubeCore

Wearing a complete set of armor, based on leather color, gives configurable effects.

An denizen extension for UltraTrader

BuildFFA [Free Sourcecode]