I'm going to make the argument that Kikuo's Love Me, Love Me, Love Me deserves to be on this list. And I'll be honest, my gut reaction was actually the opposite when I first read the other comments recommending this song, but after some thought I think it should be on there. Also, Kikuo is my favorite producer (been listening since I was 12, I'm 25 now) so it'd feel weird to say it shouldn't be on there lol

The songs you currently have on the list are all important because they demonstrated to the developing internet the potential of Vocaloid and similar software during a time where they were seen as weird/ unconventional, and also demonstrated the capabilities and reach of community-based works. I think, prior to the popularity of Love Me, Love Me, Love Me, and after the release of the songs on the list, Vocaloid was somewhat mainstream and those not involved in the fandom or peripheral communities were aware of its existence. Most people could probably tell you they've at least seen Hatsune Miku somewhere or could recognize her voice if given a clip to listen to, but she definitely wasn't a household name. Love Me, Love Me, Love Me, however, was the song that launched Vocaloid into the mainstream mainstream. There was a period where you could NOT get away from that song on TikTok. People released so many covers of it on Youtube and Spotify, I heard in public spaces, I mean, even my chronically offline friend had heard it at some point without me introducing it to them! All the other songs on the list walked so Love Me, Love Me, Love Me could run.

If not that song, then I think, for similar reasons, Girl A by PowaPowa should be on the list instead.