Couple of sites to add that sell ePub:
Name: BearMountainBooks.com
Site:
http://www.BearMountainBooks.com/store
Price: Free to $4.99
Genre: mystery and urban fantasy
Number: A Dozen or so
Support: ePub and mobi in a zipped file
Format: .epub and mobi
Notes: Store run by the Author. May add free offerings from other authors soon.
Name: All Romance Ebooks.com
Site:
https://www.allromanceebooks.com/
Price: Free to $?
Genre: Romance of all mixes and levels
Number: Hundreds? Thousands? A Lot.
Support: ePub, mobi, PDF
Format: many, but not all books have all formats
Notes: Prices are reasonable and has a nice "flame" rating so you know if it's a clean romance all the way to the other end