Just for nsfw stuff and not full porn games the first I can remember is some game that had you catch beers in a crate and the farther you got there was a chick that took off her clothes. Think that was like 15ish years ago, maybe more.
Mom/son is the og. Nothing beats that. But its nice to dabble in some less popular relationship types from time to time, like grandma/grandson or uncle/niece.
Of course having some animations in a game is better, but if that makes the waiting time much longer and the anims ain't even that good then I'd rather have none or only for scenes that are important. Like a first penetration.