These full rides were mentioned upthread in replies #9 and #18:
https://www.pvamu.edu/faid/types-of-aid/scholarships/university-scholarships/
https://www.tuskegee.edu/programs-courses/scholarships/freshman-scholarships
https://www.aamu.edu/admissions-aid/financial-aid/scholarships/_documents/academic-scholarship-brochure-2018-2019.pdf
They all happen to be historically black schools. However, full rides have become less common or more competitive generally, including at historically black schools as well as other schools.