This mod enables exchanging a quantity of items for different items. First you need to craft a Hobbesian Talisman:
Everything else is crafting recipes that include the talisman (which does not get consumed):
4 iron <-> 1 ender pearl
8 iron <-> 1 gold ingot
4 gold <-> 1 diamond
2 diamonds <-> 1 emerald
Also, logs and saplings can be exchanged in a loop:
oak->spruce->birch->jungle->acacia->dark oak->oak
