okay i waited forever to answer this because i had to really think about it. he has a ridiculous amount of good ones and they're all so unique and immersive and beautiful that it feels like a disservice to only pick one. (so i picked five of each and it still doesn't seem like enough. honestly every song he's ever put out is my favorite but i'll just pick a handful of ones that come to mind)

covers: unknown mother goose, non-breath oblige, white happy, villain, aishite..... i have a LOT of other favorites that i don't know the english titles of
originals: kirin ga shinu made, saisei, kuruoze, nugirenu, deus ex machina... and so many others...

ugh trying to choose is so hard. he literally has my very favorite voice(s) in the whole entire world. one time i got a hit tweet for saying something like 'you ever love a singer's voice so much that you feel like you're going to cry even when it's not an emotional song' and yeah that was about miyyuu. im convinced he's like an otherworldly being who's the Vocalist God on another planet and is hiding on earth or something (for legal purposes this is a joke but really there's no other explanation for that freaking insane vocal range and control)