Fun plugins I can give players permissions to use?

I just need a small list of plugins that you think are fun that players can use only if they have a permission to use it.
Simple things, nothing way massive.
Players on my server can already buy survival flight, hats, use of enderchests, and some other things.

I am creating a massive dungeon/maze and I need something special to give the player for successfully beating it. They will be given iconomy money, and some items, but its not enough. This is a very big dungeon/maze. (literally about 300x300 if not going to be more)
What makes it particularly difficult is players that enter are basically incapable of leaving the dungeon until they have beaten it.

 

CraftBook? For like elevators, gates, bridges, doors, maybe a few CommandItems you could setup that do fun things? Few extra crafting recipes? Have mobs/players drop their heads? There are many other things you could do with CraftBook.