Czechia: Tabor-Bechyne is amusing, 1500V centre cab electric hauling a single coach, sometimes railbus trailers.
And it's also a 1.5 kV branch in 3 kV territory. I believe the trains are hauled to and from the depot across the main line by a diesel shunter.
It also finishes with a rather impressive bridge over a river, enhanced by the fact that it runs over the bridge on a road. Not many places you can look out of the back of a train and see cars following along behind.
In the summer, at least in previous years, they have run historic stock (I think just at weekends), some of it in place of a regular train at normal fares.
Well worth a trip if in the area.
If coming from Prague you can probably still get there and back on a loco hauled train.
Also for not much longer: hauled Intercity in Spain Badajoz, Almeria (scenery) etc, to be replaced by S-730 units once the much-delayed cascade starts.
If those are the ones hauled by a pair of 67 lookalikes, they are quite a sight.
Narrow-gauge oddity: Tremesna-Osoblaha - CD-operated narrow gauge regular service at normal ultra-cheap fares plus a border-of-empires feel explaining why it was built in the first place (rather than a branch from the flatlands of then-German now-Polish Silesia).
For narrow gauge I'd highly recommend the Septemvri–Dobrinishte line in Bulgaria - a very scenic railway that twists and turns through mountains with lots of tunnels and a 360 degree curve. 760 mm gauge but still, so far as I know, locomotive hauled, and used very much as local transport. It feels very much like a proper loco hauled train just in miniature. You'll get even more impressive scenery in Switzerland but not, I think, a train like this.
Massively long and heavy Finnish night trains to/from the north. Up to about 12 double-deck coaches plus car carriers.
Including being able to cross the Arctic circle on a train.
I'd also add the "Alex" train between Prague and Munich.
I've only been on it when it joined/split with another route in Germany which it no longer does, but I presume that it still runs with a mix of Czech and German stock with at least two engine changes as it goes from electric to diesel and back to electric lines. And I have read that extra coaches are now added in Germany in lieu of the split, and possibly also some for local travel in Czechia (when I used it last, one carriage just ran between Prague and Plzen).
It goes through nice if not spectacular scenery, and despite linking the capital of Prague with a large city in Germany part of it is on a rather rural single track line.
At least a few years ago there were still semaphones on part of the route - which you can get a good view of by looking out of the back of the train.