Bukkit

You can edit a sign with Sneak+Right-Click. (supports 1.7 and 1.8/WorldGuard/Essentials signs)

NoServerMessages

Lightweight plugin that stop Enderman griefing.

DynamicSounds

Allow youtubers to announce that they're recording!

If you mine an ore you get the ingot! With permissions

StopTNT

Controller Blocks +, allows the player to create Control Blocks, when powered by Redstone will toggle blocks.

CustomScoreboard

helps to handle trees on your servers very easy

EasySwitch

Plugin that allows you to set custom messages that broadcast every so often.

Scare your players with a fake explosion on your targeted block!

Customize your Enchanted books

Stop Combat Loggers in their tracks with Snick's Combat Logger!

An API for MySQL

Multi-World Compatible Time and Weather Control and Vote System

BedrockRemover - Inventory remover

Enables servers to prompt players configurable surveys to provide feedback to the server admins.

JPower