Free Homeschool Readers

McGuffey's Readers

The Eclectic Manual of Methods for the Assistance of Teachers
Old Favorites from the McGuffey Readers (1-6) - useful when deciding where to place your child in the McGuffey's Readers. 
McGuffey's Eclectic Primer
McGuffey's Eclectic First Reader
McGuffey's Eclectic Second Reader
McGuffey's Eclectic Third Reader
McGuffey's Fourth Reader
McGuffey's Eclectic Fifth Reader
McGuffey's Eclectic Sixth Reader
McGuffey's Eclectic High School Reader
McGuffey's Eclectic Spelling Book 

Treadwell Readers

Primary reading and literature : a manual for teachers to accompany the primer, first and second readers of the reading-literature series
Reading-Literature Primer
Reading-Literature First Reader
Reading-Literature Second Reader
Reading-Literature Third Reader
Reading-Literature Fourth Reader
Reading-Literature Fifth Reader
Reading-Literature Sixth Reader
Reading-Literature Seventh Reader

Other Readers

A Primary Reader: Old Time Stories, Fairy Tales, and Myths Retold by Children 
Everyday Classics First Reader