This is a list of the items that can be added and what items are needed to obtain them
*** Spoiler - click to reveal ***Food Pills (Apple x 2 & Recovery Mushroom x 3)
TortoiseShell Pills (Walnut x 5 & Purple Flower x 3)
Shot Run Pills (Blue Flowers x 10 & Death Cup x 1)
Scroll of Hidden Cloud (White Scroll x 1 & White Flower x 3)
Substitution Scroll (Black Flower x 10 & Straw Figure x 1)
Sluggish Tag (Black Flower x 10 & Purple Flower x 10)
*** Spoiler - click to reveal ***Poison Tag (Purple Flower x 3 & Poison Mushroom x 3)
Sleep Tag (Recovery Mushroom x 5 & Sleeping Grass x 1)
Chakra Seal Tag (White Flower x 5 & Plain Tag x 1)
Paper Bomb (Explosive Mushroom x 6, Red Flower x 6 & Plain Tag x 1)
Bomb Ball (Expl. Mushroom x 5, Yellow Flower x 5 & Firecracker Ball)
Edit: Buying Shuriken Holsters also counts towards the total