1. Find uses for currently useless items e.g. a saddled pig can be controlled+goes 2-3x walking speed, so a saddle becomes useful e.g. a monster spawner spawns items like wood and cobble every so often (These are just examples. If there is no plugin that allows this disregard this) 2. Custom crafting recipes for unobtainable items e.g. glowstone, which is unobtainable due to a) nether not working, b) no one has survivor, and c) server shop is a rip-off could have a crafting recipe which uses torches instead of glowstone dust i.e. [Torch] [Torch] [N/A] [Torch] [Torch] [N/A] =1 Glowstone [N/A] [N/A] [N/A] (Just an example) Thanks for reading!
1, no plugins found 2, you can make a trade sign in the tradehouse or http://dev.bukkit.org/server-mods/customcrafting/