On a Mac you can press space to preview any file. QuickLook is an open source Windows program that does the same thing.
Just browse your files in Windows Explorer, as usual, then press Space to preview something. Quick Look will open quickly, showing you either the file or information about it.
Windows Explorer is still the active window, meaning you can use the arrow keys to continue browsing files—QuickLook will keep up, showing you previews for whatever file is currently selected, which is great when you need to find a particular file. There’s also a quick button for opening a given file in the default program, once you’ve found it.
You’ll wonder how you lived without this feature—at least, that’s how it is for me on macOS. Enjoy!