If you didn’t know, Apple’s macOS has a built-in keyboard/character viewer (see image above) which allows you to view characters available to you such as currency symbols, punctuation, arrows, mathematical symbols, etc. It’s also where you can view all the emoji characters available.
They Keyboard & Emoji Viewer is available in the Mac’s menubar after you enable it in the System > Keyboard Preferences dialog window.
But there’s a shortcut to bring that Keyboard Viewer up without visiting the menubar—a good amount of time savings if you use it a lot or have the menubar icons hidden with an app like Bartender.
Bring the Keyboard & Emoji Viewer up simply by hitting Control+Command+Space.
The one thing that bothers me is that there’s no keyboard shortcut to make it go away. You can’t hit Command+W to close the Viewer window because the Keyboard Viewer isn’t a typical app in that the app window is never the “active” window, and you can’t force it to be.