OpenComic - Open-source comic and manga reader for the desktop.
Comic Seer - Comic Seer is one of the simplest and fastest applications that is used for reading, viewing and managing the comic stuff.
Calibre Web - Calibre Web is a web app providing a clean interface for browsing, reading and downloading eBooks...
CDisplay Ex - CDisplay Ex is the most used comic book reader.
Tachiyomi - A free and open source manga reader for Android.
C.B.R. - Comic Book Reader - Comic Book Reader is the viewer you need to enjoy all your electronic publication.