These are required items:
-feeding dishes (one for food and one for water)
-a litter box with litter
-a litter scoop
-collar and ID tag with cat name & owner contact info
-cat/kitten shampoo/conditioner
-food & treats
These are optional items:
-scratching post (to reduce scratching of unwanted household items, i.e. leather sofa)
-catnip/cat grass (to reduce hairball)
I do not recommend a flea collar to be put on a cat because it contains pesticide. You should instead regularly inspect your cat's fur for fleas and ticks.