Okular - Okular is a universal document viewer based developed by KDE.
4K Stogram - Free Instagram Downloader for macOS, PC and Linux. Search, download or backup Instagram photos shared by any user. Follow your favorite photographers and stay tuned!
Sumatra PDF - Sumatra PDF is a slim PDF/DjVu/EPUB/XPS/CHM/CBR/CBZ/MOBI viewer for Windows.
Ramme - The Unofficial Open Source Instagram Desktop App
Foxit Reader - Foxit Reader is a free and light-weight multi-platform PDF document viewer.
vu - Dead simple Instagram client for Mac