The title says it all, come up with something useful, crazy, pretty much anything it doesn't have to consist of real minecraft items just post some ideas below. Here's a good example(I found on google):Just post things like this that you have made up *note: this thread is for fun, not for suggesting recipes to Aikar and the Devo team.
-Emerald Sword (More Powerful than Diamond and Less than Obsidian) (Durability of Diamond) -Redstone Sword (Equal Power and Durability to Iron) (Activates Redstone Objects when you hit them) -Lapis Sword (Golds Power, Irons durability) (all same as others swords but with that material) For the Rest I will use this for showing recipe (X=item O=blank) XXX XXX XXX -Mega Tnt XXX XXX XXX (9 times as powerful as normal tnt) (used for saving time) -4th Slabs (the remain leftovers from steps) OXX OOX OOO -Invisible String (One string and one invisibility potion) (Only the Placer can see it) (Crafted with 8 string and 1 invisibility potion in the middle) -Disguised Trip Wire (Trip Wire Disguised as a block) (Crafted with 8 of the block and 1 tripwire in the middle) Just a few Ideas I came up with.
Slimy Rails. Crafted like a normal rail, but 1 slimeball in the top middle and the bottom middle. Useful for slowing down tracks but keeps them going.