I can't think of any other band VNs (I love RockRobin too!), but if you're interested in interactive fiction games (text only, no art) then there are a few band game demos:
Scapegoated - set in the 70s, the MC is already part of a famous band that breaks up near the beginning of the game. The MC is set as a woman.
Infamous - the MC & their band goes on a music reality TV show (kind of like The X Factor/Pop Idol but for rock bands), their ex-friend/partner/bandmate is also on the same show. This is about to get an update with a new chapter soon, so I'd wait for that before playing.
Press Play - the story is told alternating between present time interviews and flashbacks to the past about MC & their band's rise to fame & all the problems that comes with.
Voulez-Vous? - set in 1970s Brazil, the (v messy) MC is in a disco band trio with lesbian love triangle drama lol. The MC is set as a woman (also wlw).
ST4RDOM - the MC is in a K-pop girlband about to go on their first world tour. The MC is set as a woman.