Here's another hard to find work of nineteenth century African American poetry. Or something like poetry. Joshua McCarter Simpson's Original Anti-Slavery Songs (1852) is a collection of songs intended to be sung at the informal gatherings that took place along the Underground Railroad. Simpson intended these to be sung to the tune of popular songs (often minstrel songs), hoping that this strategy would "kill the degrading influence of these comic Negro songs," as he writes in his prefatory note. The most famous of these is "Away to Canada," set to the tune of Stephen Foster's "Oh! Susanna," which had come out just a few years before.
Only a few copies of Original Anti-Slavery Songs survived; both are held in research libraries in Ohio, where Simpson lived his whole life, and which was crucial state for those escaping slavery. Simpson's second collection, The Emancipation Car (1874), expands on the project of this book, and contextualizes the songs with prose pieces. It's a little more widely available, since it was reprinted after the rise of Black Studies in the 1970's, but maybe I'll say more about it later.