I have a rather large folder containing many PDF files. Opening each and every file from Explorer seems too tedious.
Lightweight PDF viewer
There is no need to offer advanced options.
The ability to navigate in the current folder in alphabetical order by a keyboard shortcut.
Works on Windows 8.1
Bonus: Rescale each PDF to fit the viewer's window size.
For example, IrfanView and Windows Photo Viewer do have this feature.
I have already tried opening Foxit Reader with multiple PDF documents as tabs. Navigating would then work by hitting Ctrl+W to close the current tab and thereby switching to the next tab. However, it seems that Foxit Reader doesn't preserve the alphabetical order in some cases.