Quite by accident, I discovered the other night that the lids that belong to the Tupperware snack containers fit on a can of wet dog food.
The lids from mayonnaise jars fit on regular mouth canning jars. I've also read that peanut butter lids fit wide mouth jars, which I tried, but mine did not. Peanut butter lids must vary in size somewhat so yours just might work!
I love discovering useful bits of info like this!