Okular is a universal document viewer developed by KDE. Okular works on multiple platforms, including but not limited to Linux, Windows, Mac OS X, *BSD, etc.
Features:
Latest version of Okular. But sadly, it doesn't have dark theme. Edit: Now it has, thanks to recent changes.
Okular is my favourite PDF viewer. However, the icon and the Okular's design needs an overhaul.
Amazing. I particularly like the possibility to change the paper color due to my sensible eyes.