Foxit Reader - Foxit Reader is a free and light-weight multi-platform PDF document viewer.
Okular - Okular is a universal document viewer based developed by KDE.
DjVuLibre - DjVuLibre: Open Source DjVu library and viewer
Sumatra PDF - Sumatra PDF is a slim PDF/DjVu/EPUB/XPS/CHM/CBR/CBZ/MOBI viewer for Windows.
DjView4 - Standalone viewer for DjVu files.
Atril - Atril is a simple multi-page document viewer. Atril is a fork of Evince.