Tiki Cat, baby food, Nutrical, and Science Diet A/D
Even a healthy cat can go through an occasional bout of being a finicky eating. The conventional wisdom is that you should "wait it out and he'll eat when he's hungry enough." But what these laypeople don't realize is that if a cat fails to eat (or under-eats) for long enough, they are at risk of Fatty Liver Disease. This is basically a feedback loop where not eating makes the cat feel sick, and the sicker the cat feels the less they eat, which makes them feel worse. Next step: liver failure.
Then again, you might just want to give your cat a special treat, maybe for her birthday, or for a holiday!
Either way, there are several great options out there for treating a happy cat, or coaxing an unhappy one to eat.
Baby Food
Meat puree baby food (the kind that comes in the little glass jars, and smells appalling) is one of my first go-to foods in this respect. I don't know what it is about this stuff, they must super-charge it with flavor or something.
Picky cats love baby food, and you can often tempt them into trying little bits by dabbing the semi-liquid paste on their paws. It's also easy to feed in tiny amounts from a spoon, which is often easier on cats with limited mobility.
This is a super-premium canned cat food, made of whole, human-grade meat. Inside each can you will find shreds of real meat, basted with a little bit of broth. (No cheap marrow jelly here!) Tiki Cat can be difficult to find locally, but cats really go nuts for their offerings, which include grilled Ahi tuna, Ahi tuna with tiger prawns in tuna consomme, and more.
This is an ultra-high-calorie canned cat food. When it works - which to be fair is almost all the time - it is literally a life-saver. Personally, I have had mixed results with cats eating it. Unfortunately, it only comes in the 6oz size, and it seems that all my cats have had "freshness issues." Which means that at least half the can is wasted.
This is a gel food which is packed with calories and nutrition. It is a "food of last resort," for those picky eaters who are in critical shape. It can also really help jump-start an animal's appetite, many cats will eat this when they will literally refuse anything else. And the gel form makes it easy to sneak into their mouths!