By developed I mean in the same way Supergirl and Batgirl were introduced decades ago. Aquaman’s had Mera (Aquagirl not so much).
Even Wonder Woman got in on the act w. Donna Troy.
I know it wasn’t just Flash out of the Big Seven that this applied to, but J’onn finally got Miss Martian in 2006 I think, and even though there have been female GLs for some time I think it’s Jessica Cruz that broke the glass ceiling in that franchise and that took forever. But no Flash.
Like GL, there are female speedsters yeah, but none have had the kind of success I’m thinking of as I type this.
Just want to see if there’s any conversation to be had on this subject thanks.