We like the McGuffey Readers…you can find them for free at Gutenberg.org. I finally invested in a full set (they can be used through high school).
Pathway Readers are available at Milestone Books or Rainbow Resource. We have a few of them, but I haven’t used them yet. I picked some up used and am planning on using them when DD gets a little more fluent.
We also like early reader books like Frog and Toad, Mouse Soup, Owl at Home, Christian Liberty Nature Readers (I’d start with grade 1), and The Beginner’s Bible. I try to alternate some of the “fun” readers with the McGuffey lessons to keep it interesting. We also use some Dr. Seuess books, which may be a bit twaddle-ish, but my DC love all the rhyming.