XnView is a handy photo viewer app for Windows 10, as it supports a multi-lingual user interface. It supports more than 500 file formats, so you can open any type of file on your PC or laptop.

Cool File Viewer supports more than 450 file formats ... If you are fed up of the conventional RAR extractor apps, try 8 Zip. This new generation app uses cutting-edge technology for extracting ...

I didn't use it, but once I agreed to the free trial, I started having trouble with Gmail in the Windows 10 Mail app, and had to use Gmail's website instead. Then Cool File Viewer crashed ...

The free doctape Viewer iOS app lets you open more than 80 different file types using an iPhone, iPad, or iPod touch. The app is very useful, but CIO.com blogger James A. Martin found a few drawbacks.