People need to realise that Stubai and Kaunertal are closing today, or the next couple of days, they're not summer parks, but spring parks. So if you go there in the summer, you will be quite disappointed. Dachstein will also most likely be closing within the next couple of weeks.
So that leaves us with Hintertux, maybe Kitzsteinhorn, Schnalstal, Les 2 Alpes, Zermatt, Saas Fee. There are other glaciers open, but with minimal or no parks they aren't very interesting.