I think there is an RPG maker game where you are literally the cupid and can matchmake any couple as long as they're compatible or something.
Edit: It's "Baby-making time!"
Brilliant just brilliant!
Bit surprise there's no Ucchi route and I find end credit pairings to be quite adorable, make me wish there's one for Tomoko and Minami aka Fangs girl just to see how that look!
There's gotta be a galge out there where you just ship the heroines. Anyone?
Not a galge, but FE's support system allows you to put folks together and develop their relationship through various levels. Wish someone adapted that system to a yuri game, though it'd probably be a pain to write scripts for every possible combination, especially if you're gonna go for a wholeass relationship arc with contributions from the other characters. I think it'd be sustainable with 4-5 heroines, though, and most VNs with routes are obscenely long anyway.
One of the first bits of yuri/yaoi I was ever exposed to was these fanmade same-sex romance support conversations for Awakening and Fates. They had one for basically every pairing possible, even ones that didn't normally support in game. They're probably still out there on Youtube somewhere, too.
...wait, what manga is this from? or is it manhwa?
That's from a Chinese webcomic called "She is Still Cute Today" (今天的她也是如此可爱). It was translated on Mangadex, but not kept up with for a while. In addition to the female leads' relationship, that guy gets yaoi-teasing with another male character.