My cat did pretend once to eat some crisps I'd given her. She was sat on a chair looking at me pleadingly, so I put a couple in front of her and after a sniff she "accidentally" knocked them on to the floor whilst pretending to eat them.

I’ve known multiple dogs that put items in a spot, then brushed their noses over them, as if burying them with invisible dirt.

However, I figure that’s an instinctual behavior, similar to digging/burying food. Not evidence of imagination. Just evidence of dogs interacting with invisible objects.

They pretend they have toys when they have nothing at all, sometimes. And I'd argue that even playing with toys the way they do is major make-believe. Which is also something they already do in the wild - practice hunting on dead animals or inanimate objects.