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:
Great for reading PDF's. Easy to navigate, and has a very handy offset 1st page feature. It needs a lot of work for editing, though. All the editing features are difficult to use.
Renders awfully slow even compared to xreader, and lacks features compared to Evince and xreader
As it is amazing application, I feel obliged to rate it with a 5. I will forever hate flatpaks though. I wish the package version wasn't outdated
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.