I don't think that megpoid (vocaloid3) needs to be a separate character tag, since it looks like it's just Gumi in different outfits. Maybe we could just make general tags for the outfits, like we do for other outfits like neko cyber or rough time school.

vocaloid3 ?

Any changes from here on notwithstanding, there's no reason why Megpoid shouldn't be changed to Gumi.

Shouldn't it be gumi (extend), or was that just a codename?

The company changed the name officially to Vocaloid3 Megpoid, I think the reasons were that Extend felt like one voicebank instead of multiple (separate types) purchases, and plus it seemed like a Crypton thing to do.

Okay, I've changed megpoid_(vocaloid3) to a general tag.