This page lists all Recipes that can be found or looted in the game. Four more are available from the Blacksmith when he is unlocked.
Recipes are used to craft consumable items. They can grant potent effects and increased abilities for the duration of the potion.
Right-clicking a Recipe that drops will add it to the collection within the Blacksmith Crafting UI, and makes it available to all characters you create. Any subsequent copies of the same recipe that drop can then be sold or traded with other players.