One of the best hacks is to look at the websites of the climbing schools in various regions and see what climbs they offer, and in what order. For example, a common follow-up to Grossglockner might be Grossvenediger. The Hohe Taurern has many good objectives for the beginning/intermediate mountaineer and there are few, if any, cable cars to interfere with your quest for fitness.
Another great (the best) reference for this kind of approach would be the classic Gaston Rebuffat book: 100 finest climbs on the Mont Blanc Massif. That entire book is organized in the format of ever-more complex and challenging objectives for developing as an alpinist.
This is a great model to follow and I commend you for approcahing mountaineering in this way.
Best of luck,