It's very early in the game, but a possible third black-ish spinoff is in early development at ABC.
As a prequel, it would revolve around a young version of Tracee Ellis Ross' character, Rainbow Johnson. Right now, a young version of Bow will be the subject of an episode that will be filmed in March. It could potentially work as a backdoor pilot.
No casting has been done yet and ABC is still working to tap writers for it. This would be the second spinoff of the series after the Yara Shahidi-fronted grown-ish at Freeform (originally developed for ABC).
Deadline notes that if the series does end up going to series, black-ish creator Kenya Barris would be an exec producer, but not have much day-to-day involvement with the show creatively as he is now under an overall deal at Netflix.
blackish airs Tuesdays on ABC.