AA voters who were turned off by Trump's white-centric populism but couldn't bring themselves to vote for Clinton given her husband's "tough on crime" stances in the 90s and her "superpredators" rhetoric.
^^^ This, or simply Black voters who are independent thinkers. I would say Black voters (or any other voters) who voted Johnson/Weld in 2016 were not much different from those who voted for Alan Keyes in the GOP primary in 2000: young, educated, non-ideological but wedded to some American idea of "freedom" and opposed to groupthink or despotism.