Bloodsport is certainly not the first Superman villain to be adapted to Supergirl and it’s doubtful that he will be the last.
In the comics, Bloodsport is a Superman villain who is influenced by Lex Luthor into becoming Superman’s enemy.
Astra, Non, and Indigo in season 1, and Rhea and the Daxamites in season 2 — not to mention Cadmus.
That Hashtag Show has released the casting notices for these characters, as well as for yet another villain joining the roster — Bloodsport, aka Robert DuBois.