My attempt to compile an inclusive list of afrofuturist movies. Please let me know of others. Those looking for an accessible overview of the genre should check out Afrofuturism, by Ytasha L. Womack.
My best understanding is that afrofuturism features people of the African diaspora and speculative (i.e. science fiction / fantasy) elements, and combines these with a sense of hope or optimism, and / or revises narratives about black people's place in history (tragic, helpless victims) or the future (non-existent). It is not enough for a science fiction film to simply have a black protagonist (so no I Am Legend).
Many of these movies are borderline cases. Afrofuturism is a fuzzy genre, and many titles are included under the umbrella only in retrospect. Still, I have tried to take a mostly inclusive approach.