Outside of jello itself, the common desserts that contain it are chewy candies and some mousse type desserts. So canolli, mousse, and flan frequently have gelatin, along with things like Starbursts and some chewing gums, but other than that I have not found it to be a common ingredient.
Definitely not in anything like a bar of chocolate.
> ice cream
Oddly, this seems to vary a lot by country. It's rare in the US, though. Guar gum is common, though.
Usually nougat uses egg whites so it doesn't need gelatin as a protein. Marshmallows are arguably nougat, though, since they're also sugar bound with protein. Marshmallow cream usually uses egg.
All of the major nougat US candy bars I can find use egg and not gelatin.
I've seen chocolates with marshmallow in them.
The common places you might not expect it are sour cream, yogurt, fondant, and some Planters dry-roasted nuts.