Mihon - Free and open source manga reader for Android
YACReader - Download YACReader for your platform. Windows, Linux, MacOSX. And enjoy you comic books cbr cbz with the best comic reader.
Miru Project - A versatile application that is free, open-source, and supports extension sources for videos, comics, and novels, available on Android, Windows, and Web platforms.
Tachiyomi - A free and open source manga reader for Android.
Houdoku - Manga reader and library manager for the desktop
Comix - Comix is an image viewer specifically designed to handle comic books.