Bukkit

Prevent players in freecam from interacting through walls.

WorldControlManager

Provides admin hierarchy above op.

Full automated lot/rent/protection plugin

Have players protect via world guard for a price!

JailLikeHell- A simple jail plugin, with jail protection, and other features!

This plugin disables TnT!

Remove LWC protections (all) after X days that user did not login!

Oglofus Protection allows a player to place a special block, and this protects their area from griefing! (SpigotPlugin)

Kingdoms plugin for bukkit

The Voxel Box's server administration suite

Emergency

Allows players to buy, sell and rent houses with signs

BlockProtection Reloaded

Remove Them Mobs And Stop The Targeting Terror!

A chunk claiming plugin

A plugin that gives players the option to rent or buy regions from WorldGuard

Very complete lands protection plugin

Login-System

AutoDeOp will stop all players that get op when they weren't meant to will be automatically deop.