FuelCanister adds the FuelCanister. It's a cheap item which fills itself with as much coal and charcoal as possible on right click. The filled fuel Canister can then be used as a furnace fuel. It combines great efficiency and long burntime, because it smelts one item at a time, but also can smelt as many Items as 8 Stacks of coal by default (16 until 1.15.2). The max Fuel and Fuel types can be changed in the config.
Since 1.15.2, the FuelCanister can also be filled by crafting it with a valid Fuel. By default, all Items, that can be used as furnace fuel and smelt at least 1/4 of an Item are considered valid fuel, but it can be changed in the config to only accept the items, that are also allowed to be used on right-click.
In the current 1.15.2 version (1.3), refueling with right-click does not work in creative mode!