???'s Only Friend
Summons a big attack fly that can be controlled with the shooting direction-keys.
Has a chance to drop a random pickup when Isaac takes damage.
Shard of Glass
Upon taking damage, Isaac has a chance to drop a full red heart, gain 5 range, and leave a trail of damaging red creep for the current room.
Increases tears by 0.4, and spawns 2 Soul Hearts pickups.
Increases damage and grants a charged shot that fires multiple tears in the same fashion as Monstro.
Increases damage and increases the chance for a Devil or Angel Room to appear.
Tears are replaced by a laser beam that pierces through all enemies and obstacles in its path and deals high damage. Can only be fired after a short charge-up period.
Gives +5 bombs and makes all bombs Butt Bombs that fill the room with gas, damaging and confusing all enemies.
Spawns a shadow familiar that follows Isaac's movements on a 1 second delay and deals contact damage to enemies.
Gives "Turdy Touch" Effect. Enemies that touch Isaac are changed into poop.
Curse of the Tower
Causes Isaac to spawn 6 troll bombs on the floor every time he gets hit, similar to the Anarchist Cookbook mechanic.
Randomly while firing tears, Isaac will stop firing and turn red, where he will charge and release a lot of 'tears' in one go. In the burst of tears is a kidney stone which deals a lot of damage.
Spawns a familiar that follows Isaac around and fires spectral tears.
Whenever Isaac takes damage, a black ring briefly appears around Isaac, dealing damage to all nearby enemies.
Increases tears. Adds a chance to fire a high-damage razor blade.
Increases Luck by 1, grants 1 Soul Heart and spawns 2 Keys.