Bukkit

Prefix in Tablist using GroupManager/PermissionsEx

Allows restricting of certain words in chat and the ability to kick or warn the player.

MoreCats mod

NeverBuild by EPLOG

ServerManagement

Allows players in survival to fly like creative!

See how many players die on your server in real time.

A basic admin tools plugin

This plugin is exactly what it sounds like! When you reload it warns the players :D Simple and easy to install!

Craft1V1 - KitPvP

Change the default plugin messages, and block the users from seeing your plugins

Simple Warps

EasyGameMode changer /gm

Removes all dragons in selected world

A very simple and lightweight bug report system for your server.

Have different spawn points for different worlds.

After a user is inactive for "X" amount of time, his/her WorldGuard region will be deleted!

CraftAplus

Disables the vanilla OP'ing system in favour of permissions plugins!

Anti-7/Blacklist (DarkChat)