- Schoolbag can now stack (does not stack infinitely) (does not work on characters with existing pocket actives). With two or more Schoolbags, when you use an active item, that item will be reassigned to your pocket active slot.
- Infestation can now stack. Each stack of Infestation will release an additional 2-6 blue flies (does not scale with luck).
- Infestation 2 can now stack. Each stack of Infestation 2 will spawn an additional blue spider upon killing an enemy. This includes enemies killed by blue spiders.

Awesome new workshop thumbnail made by TheTurtleMelon!

- Card Reading can now stack (does not stack infinitely). Whenever the player advances to the next floor, the third portal type will be spawned in addition to the usual two. However, this effect only occurs if two portals would already be spawned by Card Reading, meaning it will not work beyond the Depths unless an effect causes treasure rooms to spawn on the floor.
- Guppy's Tail can now stack. For each additional stack of the item, there is a 33% chance (affected by luck) to spawn a chest of any random type upon clearing a room. Each stack of the item provides an additional opportunity for a chest to be spawned.
- Cracked Orb can now stack (does not stack infinitely). Upon taking damage, the Soul of Cain effect is now activated, opening up any Red Rooms connected to the current room.

-Fixed an issue with Cursed Eye's stacking

- Giant Cell can now stack. Grants additional Minisaacs when damaged.
- Heartbreak can now stack. Grants additional damage per Broken Heart.
- X-Ray Vision can now stack (does not stack infinitely). Allows Boss Rush and Hush doors to stay open beyond their respective time limits. Big thanks to PixelPlz for the code to make it work!

- Added stacking functionality for Car Battery
- Added stacking functionality for Loki's Horns (currently only works with tears)
- Added stacking functionality for Isaac's Tomb
- Updated Cursed Eye to allow Technology lasers to function correctly