Cool stuff sushi roll, I specially like koronba and nATALIE, though that Kikuo Rainbow stuff is pretty chill as well.
I'm not actively into vocaloid, so I'll just post some stuff which I came across over the years and found chill/cool/nice/whatever.
re;mo is nice, kinda shoegazy, kinda post-rocky, really lends itself to vocaloid imo.https://www.nicovideo.jp/watch/sm19491976https://www.nicovideo.jp/watch/sm19331563
(I'd recommend checking this album out)
Quadrophenia can be pretty comfy, though it's sparingly vocaloidhttps://www.nicovideo.jp/watch/sm20288269https://quadrophenia.bandcamp.com/album/fix
Always thought this one was a bangerhttps://www.youtube.com/watch?v=L9kL6AmTdbc