Extra supply crates are obtained by exchanging certain items to Ignisia. Unlike regular supply crates, these only come with one roll on the drop table.
The items players can exchange are:
In addition, handing in a full set of the Pyromancer outfit to Ignisia, (hood, garb, legs, and boots) players will receive a supply crate with five rolls on the drop table.
Note that players cannot receive some items from the Extra supply crates such as burnt page, Tome of fire (empty) or the Phoenix pet.