Accelerated Man is the speedster from earth 19 (Gotham by Gaslight/Amazonia universe), a world where supereheores has started to appear in the begginings of the industrial revolution.
Multiversity:
Accelerated Man was recruited along with the other Flashes of the Multiverse by Red Racer to stop The Superjudge after he became corrupted by The Empty Hand.
Arrowverse:
Accelerated Man works with Gypsy at the Collector Agency on Earth 19. Their job is to catch inter dimensional criminals.