Gale US History in context features resources like Notable Black Americans and The Dictionary of American Biography as credible places to learn more about important Black Americans during Reconstruction. Due to common first or surnames, be sure to check the birth and death dates to confirm each individual during your research.
The National Park Service (NPS) Reconstruction Era site contains a good list of key figures with a short biography stating their accomplishments. You can conduct a Google search for the person of interest and the NPS should be one of the first few search results.
The references listed at the end of the Wikipedia entry for the person of interest may lead to additional helpful resources.
Jordan (or Jourdon) Anderson (Gale, W)
James A. Bowley (NPS and W only)
Blanche Kelso Bruce
Octavius V. Catto
Frederick Douglass
Jonathan Clarkson Gibbs
Miffin Wistar Gibbs
Henry Hayne
Thomas Lemuel James (+ Google)
Robert Meacham (+ Google)
Sam Polite (Gale, WPA interview)
Joseph Hayne Rainey
Hiram Rhoades Revels
Prince Rivers
Robert Smalls
Stephen Atkins Swails (NPS)
William Hannibal Thomas (Gale, + Google)
James Milton Turner
William James Whipper
Jonathan Jasper Wright
Mary Bell Bythewood (NPS only)
Annie Cooper
Julia Ringwood Coston
Rebecca Lee Crumpler
Charlotte Forten Grimke
Frances Ellen Watkins Harper
Susie King Taylor
Mary Church Terrell
Harriet Tubman
Ionia Rollin Whipper
Josephine Silone Yates