Vienna, Austria
Potentially go Vienna city card to travel around public transport
Vienna city card: free travel on public transport, seven days of discounts, optional add-ons that can include sightseeing buses and airport transfer. 24-hour, 48-hour, 72-hour and 7-day options cost, respectively, €17, €25, €29 and €35 at the time of writing.
Vienna Welcome card: even more cheap. Free public transport and optional mobility service (e-scooter, etc). €14.90, €20.90 24/48hrs. Only service inside city
Vienna Pass: two days option. Free one entry to tourist attraction. Fast track entry some location. Free bus tour. 125€ per card (two days pass)