I have a candy-themed pet called Miss Candi and some carnival-type items in the TC of Agent 13, if that helps. (But I see you have most of the playsets already...)

As for more items, the Carnival Stand would be your best bet when it comes to foodstuffs, but it depends on whether you want an American- or European-style carnival or just a generic one. In UK, from what I remember, we don't tend to have things like hot-dogs, corndogs, funnel cakes and beaver tails: burgers, chips (fries), ice-cream and fish & chips are more popular, as well as pick-n-mix candy stalls. Cotton candy/candy floss is everywhere, though.

If you want to have more than food, there are some items that would fit nicely: rubber ducks for the catching games, stuffed toys for the prizes such as the unicorn or monkey plushies, the carni shirts, clown dolls or ragdolls, little cheap and tacky items like plastic whistles or inflatable hammers... Maybe some sort of ticket items?

- Thank you very much for your response! I had never thought of the different types of carnivals based on culture. :)