Bukkit

Allows you to log your chat effectively.

Allows you to rename and add lore to items and mobs

Use signs and redstone power to change block IDs and damage

Generate custom made terrain

MobSpawners

BlockSniper

The ability to set a certain block to change when you break a block.

Reward your players for being AFK

The ability to give VIPs or donors the ability to fly but without creative.

Epic EnderCrystals [PROTECTED]

CreativeWorld manages creative players by creating their own flat world

Place and remove blocks at a distance. Useful for building pixelart.

Resets The End either manually or periodically

Lays redstone for you

Create customized paths as you walk

Control time and weather in all Worlds on a server.

Limit Control Ignite

Allows map creators to interact with parts of the Bukkit API.

WorldMode - per-world game mode manager

Place blocks in the top layer of water