>>128866
Just for my own personal listing, these games are available on Steam:

Forest of soul slave 1&2
Sera's Adventure -Cave of Destruction-
Dismantling Workshop of Bio-Girl
SiNiSistar
SiNiSistar2 (in progress, check dev twitter)
The Shadow of Yidhra
CYANBRAIN
Nie -Sacrifice- (listed as "Sacrifice" in store)
The Citadel
Beyond Citadel
Alice in Nightmare Land
Nightmare
Under Party
Mad Island
DYSTHANASIA
The Dead End
Seed of the Dead (a.k.a Rape of the Dead)
Seed of the Dead: Sweet Home
Trials of the Demonic Seal

Personal recommendations:
Rule No. 2
MicroSStep
Kawaii -Ryona Trap Dungeon-
R18Plus Monster Girl You-ki chan
Eternal Dread 3
NejiComiSimulator TMA02

"Commercial" games:
Gore Screaming Show
Nie no Hakoniwa
Kara no Shoujo
Sentimental Death Loop
Last Labyrinth
Fear & Hunger 1&2
The MISSING: J.J. Macfield and the Island of Memories

Feel free to add more if I missed anything.