Henchmen Race: Not unknown, but highly discouraged in the Accord worlds on rights-of-sophonts ground, where it involves modifying or uplifting an existing species. Various people’s bioroids, on the other hand, may appear to play the trope straight, but as usually-non-self-replicating biological robots devoid of any threshold autosentience or self-will of their own, they probably don’t count as a race.