OK - Austria! This is not exhaustive, but there is still plenty of loco hauled passenger to have a go at.
RailJet all Taurus hauled, some run in pairs with the second loco in the middle. Internal ICs are dying out, being replaced by RailJets, but they are there - for example there is one a day each way between Salzburg and Graz, with a portion from Linz, booked for 1144s. EC163/164 Zurich - Graz and v.v. has an SBB panorama car in the formation and a Taurus at the sharp end (actually a pair between Innsbruck and Buchs). EC150/151 see an 1144 on Slovenian stock between Wien Hbf, Graz and Ljubljana.
The oldest electrics, the 1142s, are on their way out in Vienna now so Linz is the place to guarantee seeing them on regional services.
There are plenty of 1144s on regional services in Vienna - mainly on the Westbahn (St Valentin - Amstetten - St Polten - Wien Westbahnhof), from Franz Josephs Bahnhof on services to Gmund, and from the underground platforms of the Hbf on services between Wiener Neustadt / Payerbach and Retz / Bernardsthal. Outside Vienna, they can be found on regional services out of Graz, Linz, Innsbruck (peak hours only), Bludenz (peak hours only), Villach/Klagenfurt, and Salzburg - Wörgl via Kitzbühel. You will also find Taurus working regional services, mostly in the central and eastern areas of the country.
Diesel-wise, the 2016s can be found on Wien - Bratislava services and other local bits around Wiener Neustadt, Simbach - Wels/Linz, and also in Graz and Klagenfurt.
There are also DB 101s on German IC/EC services, plus hired-in MAV 470 Taurus locos out of Wien Franz Josephs Bahnhof on certain diagrams.
For scenery, the best of it is in the central region and the west of the country, i.e. where the Alps are! The best bits (IMO) are Linz - Selzthal, Attnang Puchheim - Obertraun Dachsteinhöhlen - Stainach Irdning, Graz - Selzthal - Bischofshofen - Kitzbühel - Wörgl, Innsbruck - Brenner, Innsbruck - Bludenz, Salzburg - Villach, Villach - Leoben and the Semmering Pass (Payerbach - Leoben).