I spend most of my stamina on hard mode for fragments/heronium. A lot of the time I forget which levels I’ve played and which ones I haven’t, since last time I checked. This results in lot of tapping to manually check each level individually.
On heroes already maxed out on fragments, there’s no way to find sources of their heronium easily either, since you no longer have this view when they’re 10-starred:
So your only option for 10* heroes is to check everywhere manually.
My suggestion would therefore be to have the number of wins left displayed straight on the world map itself. Perhaps with a label:
Or maybe just have the levels you’ve already run darkened out:
Pretty minor addition to the game, that would offer a great deal of convenience, I reckon. Especially for us heronium farmers!