Try songs by Kikuo. Most of them are dark and melancholic, but daamn they are good. Mention me if you have other genre you're interested in. I love vocaloid songs
For bigger vocaloids , Len & Rin are my favorite but others are also good . Upbeat songs can be more charming , genre doesn't matter all that much, a huge number of songs are dark . Maretu's songs are one of my favorite ~ Is that Spanish or Portuguese ? Or none ? Sounds happier then the original but still sad
Ah, Rin and Len. The first vocaloid i love and still love. My favorite is Aku no (aku no musume, aku no meshitsukai and regret message) series by Akuno-P. Akuno-P creates and amazing sets of songs. Other songs i also love from Rin & Len is Kokoro kiseki remix, Nazotoki and nazokake, feather across the season, etc
Len & Rin were also the fist vocaloid I discovered. Still higher on my list the miku for some reasons. On the other side , I really need more songs using Gackpo the only ones I can remember are Dancing Samurai and Duke of Venomsomething. Meiko and Kaito also deserve more love
Bro!!! You should check out hitoshizuku's work its fantastic Heres some personal favorites Party x Party Sister's Mercy Mistletoe~ tree of reincarnation Blessed tower of messiah Theres also the bad end series in there ^^ And i'd like to link some of my favorite covers from small accounts you should check them out Fantasy Pianist (Nekomura Iroha) ~Lucifer Selfish princess (Utatane Piko) ~KakyuuKei Setsuna Drive (IA) ~N/A Im not really sure where the source is from sorry úwù You can browse their covers maybe you can jam to it too XD Almost all the songs i recommended here are ancient lmaooo sorry bout that
I know Mistletoe , remember using it for a religion presentation Vampire's patio is also by the same person I think