Bukkit

[Clearchat] clear the chat with just /c!

Logs chat and commands

Brew alcoholic potions, get drunk and have fun!

A party plugin for your server bukkit or spigot.

CommandOverride

Light Weight - Color Chat [1.7.2] (2014)

Ultimate Hub Management

Lightweight Essentials! usefull commands and features for Minecraft! [Lightweight Essentials]

PerWorldChatPlus

CrazyLogin

Control your chat.

The best chat channel plugin in Minecraft!

Show a picture of your player's head in chat when they join! Very configurable.

ChatManager+

edit all messages of your server

This plugin allows you announce/send Titlebar or Subtitlebar as message or on join/firstjoin (also ANIMATED TITLEBAR)

A simple and easy to configure plugin that lets you announce to the server when a new player joins for the very first time.

Simple broadcasting on your server.

replacement for faction chat with faction 1.7.8+

My personal edit