Someone Who Cares Yami Yugi X Reader
You are the younger sister of Seto Kaiba, and older sister of Mokuba Kaiba. You wish Seto cared about you and would teach you to play Duel Monsters, but alas, he does not. You find someone to teach you though, and he ends up as possibly more than just a teacher.
this is basically a mainstream reader insert where the reader and yami are friends but oh my surprise, the reader starts crushing on our pharaoh and whoa he likes them back.