Bukkit

A bukkit mod to prevent players from changing their name on your mc server

Allows players to imprison or capture players into the end.

Expensive Beacons is a plugin designed to replace how beacons work by having multiblock structures

Citadel is a mod that allows players to protect blocks but also allows players to break them.

Better Associations is a plugin designed to associate players based on ip.

Juke Alert is an add on to Citadel that lets you create snitches.