ラース

Soma fantasy recommendations:
Action-focused:
Anything by Type-Moon is a must-play, but, unfortunately, nothing is on Steam.
Rewrite
Tokyo Babel is pretty interesting in what it does, but it's not for everybody.
Drama-focused:
The House in Fata Morgana is absolutely amazing
Katahane, whenever the official version is finally released
Fault series, though it's incomplete, unfortunately

That's very subjective, you know. Steins Gate seems to be top 1 on VNDB rating right now, but, having only watched the anime, I often wonder why people rate it so high.
Are you looking for some genres in particular? There are tons of high-quality VNs out there.
Recommendations for sci-fi:
I definitely recommend the Muv Luv series, but it's better not to get into it as a total beginner.
Baldr Sky seems to be pretty good, though I personally couldn't read it due to some anxiety problems.
Ever17 would be a good choice, but it's not on Steam. Root Double might work as a replacement, though I haven't read it, so I'm not sure about its quality.
There's also YuNo remake.

I believe the OP was asking for translated VNs with Japanese voice acting.

Uhh... https://vndb.org/v?q=&ch=&f=032gen3gja8ESx2&s=26w

VNDB can find a lot