Wikia

Pick Ups are random items that are dropped by enemies, spawned in rooms, given by beggars, won in slot machines/shell games, and found in chests, fires, poop piles, and blue rocks. They are consumed by walking over them. In the case of hearts, you will not pick up a heart or attract it with Magneto unless you are damaged.

Note : Only 12 hearts will be displayed at a time (regular and soul hearts). You can only have a maximum of 12 regular hearts. Soul hearts are not restricted in this way.

Basic Pickups include:
Hearts	Keys	Coins	Bombs

Item Icon	Item Name	Effect
	Half Heart	Fills your heart containers by half a heart. Randomly replaces Full Hearts when dropped.
	Full Heart	Fills your heart containers by a heart.
	Soul-Heart	Gives you 1 additional, non-refillable heart. Randomly replaces Full Hearts when dropped.
	Eternal Heart	Grants 1 Eternal heart segment. Collecting another or completing the floor will turn this into a Full Heart Container. Lost before normal hearts but after soul hearts. (Wrath of the Lamb only)
	Key	Used to unlock locked chests, doors, or blocks.
	Golden Key	Allows you to unlock any door, chest, or block on the current floor without needing or using normal keys. Randomly replaces a normal key when dropped. (Wrath of the Lamb only)
	Penny	Gives you 1 penny.
	Nickel	Gives you 5 pennies. Randomly replaces a normal penny when spawned.
	Dime	Gives you 10 pennies. Randomly replaces a normal penny when spawned. (Wrath of the Lamb only)
	Bomb	Blows up an obstacle (rock, doors etc.) or damages enemies. Can be pushed by various things.
	1+1 Free	Gives you 2 bombs. Randomly replaces a normal bomb when spawned.
	Troll Bomb	Acts like a lit bomb, but doesn't damage certain enemies, such as Pride. 10% chance to replace a normal bomb when spawned.
	Super Troll Bomb	Acts like a troll bomb, but follows the player around the room. 5% chance to replace a normal bomb when spawned. (Wrath of the Lamb only)