If you'd like to make an application that does this yourself, here is how. And it gives you a chance to discover how to use the Macintosh built-in programming language, AppleScript.

Here are the steps.

I promise, this is easy.

Yes, you can!

Open the AppleScript Editor
It is in the Utilities folder. You can find it two ways:
1. from the Finder, under the menubar selection GO, pull down to Utilities.
2. Open the Applications Folder. Utilities is a folder in the list.

In the Utilities folder, click on the AppleScript Editor to run it.

In the Editor, type the following two words:

choose color

(Be sure to use the American spelling for colour.)

In the Editor, choose Save As...
change the File Format from 'Script' to 'Application'

Give your program a name in the Save As: box (probably 'Color Picker')

and save it anywhere you like, but probably save it to your Applications folder.

That's it.

Run the program and the Color Picker stand-alone application will pop up. It is a very tiny app, so it appears almost instantly.

This works because the Color Picker is part of your OS. Many programs use it, but there is no stand-alone application. Well, if you do this, you'll have your one stand-alone application. Free.