Yusuke and Keiko
Kuwabara and Yukina
Botan and Koenma
sensui and itsuki
I know a weird one but I always loved the fact that itsuki loved sensui even after sensui died
These are my favorite couples in Yu yu hakusho. I have one more which is Kurama and hiei but I could do a whole card on just them so I didn't put them in this one.