Lets Go! My Harem Farm - pretty much all of the townsfolk can be impregnated. Exceptions are one child, one senior lady, and two men.
Greener Pastures - story VN with a monstergirl* harem. All can be impregnated repeatedly, some scenes with the children once the first are born.
Corrupted Kingdoms - humans and monstergirls* as partners, I think pretty much every partner can be impregnated. Although I'm not sure how much that holds up with the second chapter, haven't played that yet.
Neko Paradise - monstergirl* island, a lot of which can be impregnated.
Haramase Simulator - takes place in an ever-popular "birthrate is down"/"only a low number of men is born" setting. I think all persistent characters have pregnancy scenes. Although it is abandoned, the content for the existing girls is pretty complete, and you can easily put a dozen hours or more into it.
*) monstergirls here are mostly of the humanoid with animal-ears/-tails/-eyes variety, not
monster monstergirls. As an example, the arachne in Greener Pastures has spider-like eyes, but not the lower body of an arachne like in Monster Girl Encyclopedia works.
