I found these cans of Nature's Variety Instinct Limited Ingredient Rabbit Formula cat food at my local auction house. Yeah, I know that's kinda weird. They sell a bunch of totally random stuff aside from the auction items, most recently I got several cans of Surge soda and a bunch of bully sticks for the dogs. Anyway, these were $0.40 per can, not expired, and a super great deal.
Nature's Variety offers some of the few limited ingredient diets for cats, and the foods they make are quite high quality. They're also super expensive, which makes me glad that neither of The Hellions has food allergies.
The limited ingredient rabbit food is made from rabbit, peas, vitamins, and minerals. Nature's Variety also makes an Instinct rabbit-based cat food that contains pork, and the labels are very similar.
I'm a fan of Nature's Variety and the Instinct product lines, they're pricey but worth the money if you're battling food allergies. Brisbane, who was allergic to everything, particularly loved their canned dog food. This company does not own their own production facility, their cans are co packed by CJ foods, along with several other brands.
This is a loaf-style food that will appeal to a lot of cats. Mine go crazy for it, but they also just love food in general. I would absolutely try this for a picky cat, especially if I really needed to get them to eat.