calibre - Ebook manager, viewer & converter
NeeView - Display two images simultaneously
FBReader - FBReader is an e-book reader for various platforms. Features:
ComicFlow - ComicFlow is an iOS app that allows you to read comics by opening .cbr or .
ACBF Viewer - Comic book reader.
Sumatra PDF - Sumatra PDF is a slim PDF/DjVu/EPUB/XPS/CHM/CBR/CBZ/MOBI viewer for Windows.