Trinkets

A trinket is an item Isaac can hold that provides some sort of passive effect. Trinkets were introduced in the Wrath of the Lamb DLC. Isaac can only hold one trinket at a time, unless he has Mom's Purse, an item that lets him hold two trinkets. Picking up a trinket while you are holding one causes Isaac to drop the old one, much like how Pills and Tarot Cards work.

Once you find a trinket, you cannot find it again in the current run (with one exception: see Polaroid). Once the trinket pool has been emptied, all Trinket drops will be replaced with Tarot Card drops.

• Ace of Spades - Has a 10% chance of changing a room drop to a tarot card. Also has a 33% chance of adding a tarot card to a chest.
  
• Bloody Penny - 50% chance of dropping half a heart when picking up a coin. Useless as ???. Unlocked by clearing the Cathedral as Samson.
  
• Burnt Penny - 50% chance of dropping a bomb when picking up a coin. Unlocked by completing the Large Marge challenge.
  
• Cain's Eye - Has a 25% chance of activating The Map and the Compass when you enter a floor. Unlocked by clearing the Chest as Cain.
  
• Cancer - Significantly increases fire rate. Can boost beyond max.
  
• Child's Heart - Has a 10% chance of changing a room drop to a random heart drop. Also has a 33% chance of adding a heart drop to a chest.
  
• Counterfeit Penny - 50% chance of adding an extra penny when picking up a coin. This trinket is only found in golden poop, and it has a 33% chance of being there, provided you haven't already found one. Unlocked by completing the Isaac Was Good Today challenge.
  
• Cursed Skull - Teleports you to the last completed room when you get hit and go below 1 red heart. Activates every time you get hit as ???, or when you have 0 heart containers.
  
• Curved Horn - Adds 2 points of base damage before overall multipliers but after character multipliers. Unlocked by clearing the Cathedral as Judas.
  
• Eve's Bird Foot - Has a 5% chance of spawning a Dead Bird-like familiar that chases enemies every time you kill an enemy. Unlocked by clearing the Chest as Eve.
  
• Fish Head - Spawns one blue suicide fly every time you get hit. Suicide flies can do up to twice your base damage. Unlocked by completing the Lord of The Flies challenge.
  
• Flat Penny - 50% chance of dropping a key when picking up a coin. The key has a 2% chance of being golden.
  
• Goat Hoof - Adds .15 to your speed stat. Can boost beyond max.
  
• Isaac's Fork - Has a 10% chance of healing half a red heart when you clear a room. Useless as ???.
  
• Isaac's Head - Spawns a familiar that resembles Isaac's head. Fires base damage piercing tears. Unlocked by clearing the Chest as Isaac.
  
• Judas's Tongue - Devil deal prices become 1 heart. 3 Soul Heart deals remain unaffected. Only affects new devil deals generated after picking up the Tongue. Unlocked by clearing the Chest as Judas.
  
• The Left Hand - All chests and locked chests become Red Chests. Unlocked by defeating Ultra Pride.
  
• Liberty Cap - Every room, there is a 25% chance of activating one of the following effects: Mini Mush, Odd Mushroom (Large), Odd Mushroom (Thin), Compass (bug, should be Magic Mushroom).
  
• Lucky Toe - Increases room drops by 10%, or by 2% if you have both positive luck and the Luck Foot. 66% chance of adding an extra item to a chest. Unlocked by completing the 7 Years Bad Luck challenge.
  
• Maggy's Faith - Gives you an eternal heart at the beginning of every floor. Essentially rewards players for clearing floors without taking (red heart) damage. Unlocked by clearing the Chest as Maggy.
  
• Match Stick - Has a 10% chance of changing a room drop to a random bomb drop. Also has a 33% chance of adding a bomb drop to a chest.
  
• A Missing Page - When you get hit, 5% chance of activating the Necronomicon effect, dealing 40 damage to all enemies.
  
• Mom's Pearl - 10% chance of turning a random heart drop to a soul heart. Stacks with Eve's bonus and the Mitre.
  
• Pinky Eye - Tears have a 10% chance of being poisonous. Pinky Eye tears deal twice as much poison damage as Common Cold.
  
• The Polaroid - When knocked to half a heart of red health, activates a Book of Shadows shield effect. Lasts half as long as Book of Shadows. Always activates as ???, or when you have 0 heart containers. Needed to enter The Chest. Always dropped by Mom, unless the trinket pool is empty. Unlocked by clearing the Cathedral six times.
  
• Push Pin - Tears have a 10% chance of having both the Ouija Board effect and Cupid's Arrow, meaning they can go through rocks and obstacles and pierce enemies.
  
• Red Patch - When you get hit, 20% chance of activating a Razor-like effect, boosting damage. Acts as if you used the Razor 1.5 times.
  
• Rusted Key - Has a 10% chance of changing a room drop to either a key or a locked chest. Also has a 33% chance of adding a key/locked chest to a chest.
  
• Safety Cap - Has a 10% chance of changing a room drop to a pill drop. Also has a 33% chance of adding a pill to a chest.
  
• Samson's Lock - 6.66% chance of activating a Bloody Lust-like effect when you kill an enemy, boosting damage. Boosts about twice as much as Bloody Lust does. Unlocked by clearing the Chest as Samson.
  
• Tick - Bosses spawn with 15% less HP, and heals 1 heart when you begin a boss fight. Cannot be swapped out for another trinket.
  
• Umbilical Cord - At half a heart and no soul hearts (or half a soul heart, no red health) activates Little Steve, who follows you firing homing shots that do base damage.
  
• ???'s Soul - Spawns a familiar that resembles a ??? ghost. Floats around the room, firing spectral homing tears. Can take a few of your other familiars and have them follow it instead. Unlocked by clearing the Chest as ???.