This is a huge subject, even just limiting yourself to American slavery. The largest corpus that's readily accessible are slave narratives. These are the stories of individual enslaved people about what they suffered and what they knew and saw others go through. The most famous, by far, is Frederick Douglass'.

For a really complicated situation, I'd recommend the Crafts' Running a Thousand Miles for Freedom. They're a married couple. She can pass for a young white man, so they dress her up as one and she takes her husband as her enslaved valet. They go North to Boston, with Ellen Craft getting some romantic interest from a pair of southern belles along the way, and then have to flee from there to Britain after the Fugitive Slave Act is passed. The book is traditionally credited to William, but it's pretty clear that he's covering for her having ideas that were not acceptable forms of femininity in the era and she probably at least co-wrote it.

I would recommend strongly against the narratives recorded by the Works Progress Administration. They're the recollections of people enslaved as children, decades later. Those decades later happen in the Jim Crow South, where white interviewers who have personal connections to their former enslavers ask them loaded questions. Occasionally you get candid answers anyways, but telling things straight in that environment was a considerable personal risk. They're not useless as sources, but are much more problematic than usual.