Almost all institutes within the NIH provide research supplements to promote diversity in health-related research. Diversity supplements apply to existing multi-year NIH grants (like R01, U01, PPGs), but generally require at least two years remaining on the grant period.
Visit https://grants.nih.gov/grants/guide/pa-files/PA-16-288.html for the list of eligible parent awards.
Applications are relatively brief and generally need to propose research that is related to the overall aims of the existing project. Eligible individuals are URMs and those from disadvantaged backgrounds. Levels of training supported vary from undergraduate all the way up to junior faculty, with salary support approaching that of a K-award. Each institute may have slightly different instructions and guidelines.
Visit https://grants.nih.gov/grants/guide/contacts/PA-15-322_contacts.html or contact the institute Program officer for guidelines and eligibility.