Namco high was the first more mature VN I played. It's not exactly adult but it has some cool themes that really hooked me. I can not for the life of me remember where I got it from.
I feel NTR can be okay. I usually feel a strong disconnect from the character it's happening to, so I can enjoy watching it happen to someone else, but wouldn't want to happening to my self insert if that makes sense.
Man's best friend, it's by the same author as "kings tale" it's pretty good. You could try "But I'm the bad guy" it has a scene with a dog and you can rape the family members of a friend.