Materials are consumables in Dust: An Elysian Tail that are used in crafting recipes from blueprints to craft armor, augments, rings and pendants. There are 42 in total and they are dropped by various enemies throughout the game or can also be purchased from merchants once they have been catalogued.
The first sale of an item that hasn't been catalogued will grant slightly higher than the usual selling price.
Some items are "common" and can be dropped by all enemies; some are specific to one type of enemy, usually indicated in the name.