macOS: You probably know that Command-Tab brings up the app switcher, but did you know you can drag files to it?
Turns out you can! First click a file and start dragging it, then press Command and Tab to bring up the file switcher, continuing to hold down Command. You can drag your file to any compatible application, like this:
Tim Harwick, writing for MacRumours, pointed this out to me for the first time, so full credit to him.
There are a few other hidden features in the app switcher—my favorite is quickly closing programs. Bring up the app switcher and keep holding command, then press Q to close an app.
Here are some more essential macOS keyboard shortcuts, if you want to keep diving in. Enjoy!