Miku is notable for having received 4 costume upgrades after her initial V2 release (Append, V4X, Chinese, and NT).
Miku is the biggest example of this, though each character has a dedicated fanbase and years' worth of fan art and other fan-made content behind them.
KAITO and MEIKO take this even further, due to being the only Crypton Virtual Singers who don't have a template assigning them age or an implied background like Miku due to the two predating the 'Character Vocal Series'.