Interesting, I was under an impression that all games on the list are where incest occurred with the protagonists but you are saying the list also included games which have incest that does not involve playable protagonist(s) at all, at least not as a partner in such relationships (sexual or not).
So I did a quick scan of the list for M/D then S/S tags and found very few games here at all that contain only one or the other. Only three games truly fit the Male Protag & only F/F incest description, and two of them (Pervert Action Legacy and V.I.R.T.U.E.S.) were submitted by me. The other (Man's Best Friend) would have fit this description in the kinkiest way (Canine Protag!), but the dev hasn't updated that game in a year and it has no actual incest yet with the all-female family. And there's Movie Night, which is really a third person kinetic novel.
There are almost certainly more games like this out there though... The Anomalous Dr. Vibes, for one, has a male MC who in not related to anyone in the game, but gets a great threesome with twin sisters late in the game. In
Almost Dead, you get threesome and straight up lesbian action from twin sisters in the game.
And there are a number of games on the list that fit the spirit of what I was referring to, though.... where much of the "incestual pleasure" in the game is derived from the MP's corruption of other people's families. Solvalley School is the epitome of this, as the MC's sister and mother are both step (no patch) and have few scenes compared to those with your female classmates and their sisters/mothers. HS Tutor and especially Corruption (where your sis and mom are pretty much afterthoughts once you enslave them) kind of follow the same model. NPC female incest is so common in games of all types, yet seems so under-appreciated by the incest community.
