There's "Sun Bay City", but it's kinda being remade from the ground-up, or so I've gathered, and there's no dickgirl option. On the flip side, you can play as either a guy or a girl, there's some domination and you can freely travel around the game world (though there's not much content so, yeah).
Another suggestion is "LifePlay", but it's more of a 'click this to go there and do this'. Still, it's 3D, has dickgirls, lesbians, you can create your own character (girl, guy, dickgirl, as well as mild fantasy options: elf, orc, vampire), and there's a whole bunch of fetishes to go with. It's a bit heavy on the rig though, and since it's effectively developed by a single person, it still needs work to be a proper life-sim, as the author claims it to be, but it's still pretty nice and playable.
I've come across something called "Magissy", I think it's a high-fantasy RPG with a sex-mechanic, but I haven't played it.
There's something called "Openworld Project", apparently a 3d-person sandbox where you play as a girl and have to seduce and have sex with other girls. Haven't played this one yet either. Then there's something called "Girl life", you play as a girl (or a genderbent guy) and have to build a new life in 'the city'. I don't know if it's 3d or not, I think it's text-based though. Then there's "Ferity world", which is also some kind of third person, high-fantasy arpg, but I haven't played it either. And there's Grand Cutie Anal, a parody of GTA, I think.
That's all I can think of at this rate. Then there are a few adult mmo's, but I don't like those myself, so I can't suggest them.
