Hm. One kinda gross thing, I guess, that I sorta like but rarely see is when a dude blows a wad, and it's not magically cleaned off the person that it landed on in between scenes. Games, manga, whatever--it's like the fastest drying semen in the world or something. I guess it's implied that someone wipes down between a blowjob and sex, or whatever. I mean, it's porn--the impracticalities and undesirable parts of real life don't really need to apply.
Still, there were these 2000s-era games by a Japanese group (Soft Circle Courreges--always thought the "soft circle" part was a little redundant but that's part of the name) that not only drew cum sorta like it looks in reality (instead of white glue, paste, or dijon mustard), but they let you control when you cleaned it all up. If you had the girl give two blowjobs and then switched to the anal scene, she'd have cum on her face and mouth when the scene started. If she gave ONE blowjob she'd have LESS cum. It's not revolutionary, but it was fun to play around with. I imagine it took a lot of art-time, too, although the game did have something like ten or twelve scenes.
I guess to an extent it was a combination of that and actually being able to sorta direct the porn a little bit that I enjoyed. Probably my favorite translated to "Spiral Staircase."
Naturally, this is a pretty specific (and therefore rare) thing to be looking for in porn, so it's more of a nice thing when it happens than something that I expect to find.