Furnaces

Double Furnace-Furnaces take too long to smelt items, so you could make a double furnace. It is made like double chests and will take 2 slots of fuel and will smelt faster. Would have a regular furnace on one half and a grate on the other.

Compressed Furnace-It is crafted with 2 pistons a lava bucket and coal blocks. It has a chance of giving you more items. Looks like a dark furnace with grey bricks.

Eco Furnace-Is crafted with leaves and diorite. Will make fuel last longer and could use vegetables as fuel. It would look like a white furnace with lime green designs.