Bukkit

Custom Join and Leave Messages with Welcome Message to the player!

Gives warning if tools, armor piece or elytra reaches an X% of the durability

Broadcast

Let your players know commands for ranks on your server!

Gives people tags!

Limit the rate in which player's can send messages & commands!

This is a very simple chat manager plugin, and more features are bound to come. It is a chat manager that is easy to use, and easy to install.

Bukkit

Mute the entire chat!

Type Faster!

This deletes the /pl command so other players cannot see what plugins you have on your server.

A powerful permissions system addon for Essentials/PEX/etc

NetherrackDug

UseIt

ChatWriter

Ever wanted special characters in your server?

New users take a quiz and admins review their answers.

Provides free configuration , although it's made for begginers. Check this out.

PerWorldMessages

FlipACoin Plugin