Bukkit

The official Manhunt plugin

Inception is a plugin to allow world overlapping

Add more explosives to Minecraft!

QuickTrade

A fully customizable crates plugin

Create secret bases and hidden areas with GhostBlocks! These blocks look normal but can be walked through—perfect for secret entrances, traps, or hidden rooms. Only operators can manage Ghost and EntGhost blocks.

Teleport using buttons with price/reward/custom messages

This plugin allows players to store maps, records, and books of all types in those once useless bookshelves.

Adds more armors to the game

Yet another LifeSteal plugin.

Create hotels and rent out rooms to other players

Skillz

Order allowing you to leather your items

Sentry is a Citizens2 Character that guards against mobs and players

Enchanted Customs

A server mod that comes with many useful commands. This plugin is still inDev.

Add real-time display of mobs to Dynmap maps

ArchonCrates, the most popular crates plugin.

DrugsXL adds fun drugs to Minecraft!

Create turrets that automatically track and shoot enemies and mobs!