Prince, noble house son, rich family, powerful clan reading list: SOTR ATG Breakers Joy of Life Dragon-Marked War God BAFTLIAW Chaotic Sword God LLS PMG RW LXY
"Observation Record of a Self-proclaimed Villainess' Fiance" - This is a reincarnated-into-otome-game-villainess story where the Reincarnator decides to follow the villainous path because she loves the prince. It's told from the perspective of the sadistic prince himself, who loves her/finds her a good source of entertainment, but still has to make sure she doesn't cause too much trouble.