Those are the kind of NTR I like, here's what I can remember:
Manga/CG Set
[Aloha Soft] Shiranu Ma ni Dosukebe Kaihatsu sarete ita Boku dake no Seishori Maid
[Aloha Soft] Boku no Shiranai Kanojo-tachi no Houkago
[Youkai Tamanokoshi (CHIRO)] オレが主人公!!(じゃなかった・・・)
[ジミーキミー] バカにしてた後輩に彼女と幼馴染と母親を寝取られる話...