The question is more what can you sell. Then you don't really have the choix of which affiliate program they use. Eg I've sold Udemy courses, so registered for Linkshare. There are plenty of other products to promote in that program, in a lot of industries (insurance, travel, retail).
Can you find funny gadgets that sell on amazon?
So you think Amazon is the best choice?
The question is more what can you sell. Then you don't really have the choix of which affiliate program they use. Eg I've sold Udemy courses, so registered for Linkshare. There are plenty of other products to promote in that program, in a lot of industries (insurance, travel, retail).