1º Kichikuou Rance (albeit the gameplay didn't age well)
2º Daibanchou big bang age
3º Bunny Black
4º Kamidori alchemy meister
5º Magikoi series
Special mentions:
-Oyako Rankan
-Monster girl quest
Special mentions (concept edition):
-Life is paradise
-Desire dungeon
Personally I still don't have any english origin game that comes even near my top, the one that could go a bit towards it would be Trials in tainted space, but still it lacks in many aspects that I would say it's fundamental.