Kobo is a global eBook seller and perhaps the most comprehensive alternative to Kindle. Its bookshop Kobo.com sells both DRM and DRM-free eBooks.
The site doesn’t include any official way to separate the DRM from DRM-free titles, but you can search for DRM-free eBooks through our unofficial Kobo search page.
Kobo also make quite nice eReaders which can read almost all eBook formats (including DRM-free ones), and let you borrow eBooks from public libraries. You don’t have to use these though, as DRM-free eBooks can be read on any manufacturer’s device.