Not Enough Items (NEI)

The NotEnoughItems mod - aka NEI, is a mod that shows the crafting of blocks and items both from the game and from mods, in fact the same TooManyItems that was popular on older versions, and JEI that is popular on newer versions of the game.

With this mod, you can see the crafting of any item in the game (and even items from mods) on the R key, after hovering over it with the cursor. (but you can customize this key in settings)

The mod also shows a very handy list of all blocks and items on the right of any inventory, and on the left you can quickly switch the game mode, turn on day or night, turn rain off and on. The mod can show where this item is used for crafting on U by hovering over the item. There is also an enchantment, which is opened by pressing the X key by hovering over the item to be enchanted (pick, sword, armor, etc.).