calibre - Ebook manager, viewer & converter
Altarsoft PDF Reader - Altarsoft PDF Reader is a simple to use PDF files management program that allows its users to view PDF files, encrypt the files and even annotate these files as well.
Apple Books - The all-new Apple Books has been redesigned to make finding, reading, and listening to books a beautiful, effortless experience on iPhone and iPad.
eXPert PDF Reader - eXPert PDF Reader is a free to use PDF reader and views for the Windows operating systems.
OverDRIVE - Make workspaces and sites automatically from Google Drive
Xodo - Try easy-to-use PDF tools that keep your documents safe. Work with your important files across all platforms and devices with the ultimate all-in-one document solution. Your productivity lives at Xodo!