OSTs:
One piece, Naruto, Bleach, Attack on Titan, Hajime no Ippo, Dragon Ball (classic, Z, Z part 2, GT but not Super)
Demon Slayer only OST I like is the one of Upper Demon 3 from the train arc.
Intros:
Dragon Ball (classic, Z, Z part 2, GT but not Super), Hajime no Ippo (I guess only the last intro I don't like it), Attack on Titan
One Piece only intro I like is the USA/brazilian rap for 4Kids.
Naruto only intro I like is the Hero Comes Back from Shippuden first intro (he wasn't even a hero).