Other than the ones with the tag (Incest) as you pointed out the quick answer would be rape to various degrees/fashions
I'll try to break a few down, but as I have not played the games fully I might mislabel some.
(I'm going to use ? = unsure, * = potential/optional, and *? = uncertain if it's optional and make use of this for future recommendations)
Feminist F-ist Is quite simple as nnt1996 pointed out it contains rape or at least so say the tags I don't remember much of the game other than the fighting dialog gave me a good laugh. I think most if not all scenes are bought with money earned after the fight so it can be avoidable, but then it's just a fighting game where you strip your opponent. (Rape*?)
Introducing An Apprentice Incubus game seems to have some "romance", but I really can't get myself to play these games at the moment so I have little experience with it. (Rape, Reverse Rape? Loli, based off tags Futa/Trans, and Shota? It depends on if you would call the protag a Shota or not) idk why I initially included it other than the slightly fluffy dialog I saw at times.
Nemurimouto Just adding this one again to give a bit more substance. The game feels empty atm (it is v0.06) so some scenes seem to be near obvious rape, but then others are too absurd to be real and make me skeptical. All scenes should be "optional" as they would need user input to initiate (or so I think), but also some aren't as obvious.
Now the SEQUEL games (that I have played) are a mixed bag, but they all share one tag (Reverse Rape) They do have some nice dialog and romance routes/"endings", but they are a powder keg of different fetishes so user/consumer/player be warned.
I hope my breakdown was enough and I'll try to add the more sketchy tags at the end from here on out.
For future reference should I add the tags at the end of my review such as
EXAMPLE GAME yap yap yap desc
(TAGS)
or is the way I have done it now acceptable? (I'm leaning more toward the new format personally)
Also, I don't know if games found on Itch are fine as
Goddesses' Whim (Loli?) or maybe
Living in Viellci (Loli and the game is heavily in-dev so art is changing at times) MIGHT work, but most are just Renpy + Koikatsu VNs that I would need to scrape into for "proper" tagging and honestly I have very little drive/motivation for doing that rn.