calibre - Ebook manager, viewer & converter
CDisplay Ex - CDisplay Ex is the most used comic book reader.
FBReader - FBReader is an e-book reader for various platforms. Features:
YACReader - Download YACReader for your platform. Windows, Linux, MacOSX. And enjoy you comic books cbr cbz with the best comic reader.
Google Play Books - Google Play Books lets you search, preview, and buy millions of books using Google Book Search.
Tachiyomi - A free and open source manga reader for Android.