Yomikiru is an offline reader for already downloaded comics, manga, webtoons and epub. Supports continuous vertical scrolling mode with no gap in between images. Supports drag and drop of files.
Tachiyomi - A free and open source manga reader for Android.
OpenComic - Open-source comic and manga reader for the desktop.
IrfanView - IrfanView ... one of the most popular viewers worldwide.
YACReader - Download YACReader for your platform. Windows, Linux, MacOSX. And enjoy you comic books cbr cbz with the best comic reader.
CDisplay Ex - CDisplay Ex is the most used comic book reader.
Mcomix - MComix is an user-friendly, customizable image viewer.