Well there is "Tangled Up II"
That would actually be tagged "pregnancy" by the definition you guys are giving. It's a serious grindfest and to some people unplayable without the walktrough. (I can attest to that I've done 100+ days my first playthrough not knowing wtf I was supposed to do). If you can forgive the grindfest, and play with a walktrough straight off the bat you will LOVE the pregnancy content even the mood swings because sis got all these pregmones making her crazy

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It's my first post on this website so about me:
I prefer Ren'Py VN with incest, mom love, sis love, and creampie. But for me impregnation and/or pregnancy are a must.
I literally can't bring myself to grind trough DMD simply because I couldn't give a shit about all that grinding if nobody is getting inseminated
Good now that's off my chest here are some of my inputs off the top of my head so I might get a few wrong:
Incest Story 2 -
(RPGM, impregnation) Yup RPGM sucks but it does have a nice round belly end if you're on the correct ending
Taboo Request -
(RPGM, impregnation) I honestly haven't finished it yet the constant "buttt mommyyy" whining annoys me
Parental Love -
(Ren'Py, impregnation) You're forced to Harem route, not optional, there is an "inseminate her" dialog though
My Legacy -
(Ren'Py, impregnation) Too short ...but right up my alley, go forth and impregnate EVERYONE, yes please!
Tangled Up II -
(Ren'Py, pregnancy) Follows up on the first one's pregnancy, now you have a baby and you're inseminating gf again.
Cohabitation -
(RPGM, impregnation) It's designed to play like Ren'Py so full point click. All options can get impregnated.
Lab Rats -
(Ren'Py, impregnation) Borderline pregnancy as you do get to bang them while pregnant during the ending.
My New Roommate - (Ren'Py, impregnation) Short story easy to fail without walktrough but has 2 pregnancy endings.
I'll keep updating the list if anyone wants me to. I'm currently exclusively playing games with impregnation/pregnancy content that's why I have a decently vivid memory on them, I've played that entire list just this week.