Bloodstained really smacked me right in the nostalgia with its music (thank you Yamane, and the other composers also), and the games were actually good fun
I was late to the PS2 games (had Gamecube/GBA/DS growing up), but their OST's are
This cover to Successor of Fate is great (I do love the GBA version in its crunchiness still). The whole game felt like a confusing fever dream imho, but I still liked it, it was an experience
Lament of Innocence cover for good measure
Sinking Old Sanctuary as arranged in Legacy of Darkness is nice
LAST ONE, otherwise I'll keep adding to the list like the autistic fanboy I am (play Order of Ecclesia if you haven't)