I think it depends a lot of what kind of magical stuff it sells. Do this shop manufactures their magic objects and sell them?, do they sell magic ingredients?, a mix of both?, a specific line of products?
1-completed magic items: magic weapons, mystical amulets, crystal balls, etc....
2-ingredients so wizards can craft their own stuff: magical ingredient like a dragon`s claw, trapped fairies, cauldrons,
3-example of a specialized shop: potion shop: magic ingredients, cauldrons, bottles, completed potions for the ones too busy or lazy to craft them themselves, any creature that can be a magic ingredient or a source of said ingredient. (don`t put the baby dragon next to flammable ingredients)
3- any category: spellbooks, wands, crystals, scrolls
bonus random crazy idea: Ikea golems, build it yourself, we give you the pieces. Make sure you read the instruction manual 