Download all fonts

It's not possible to add all the fonts at the Adobe Fonts web site in one click. I would strongly not recommend adding all of them either. Just like it's not great to have too many fonts installed in a computer's operating system having too many fonts added from Adobe Fonts could increase chances of computer performance issues.

Then there is a practical matter of managing the fonts in the Creative Cloud desktop app. Fonts that need to be used with other applications not made by Adobe have to be installed using the CC desktop app. That's currently not all that easy to do. Scrolling through the list of fonts is often a hassle (due to a scroll bar that rarely ever makes itself visible). I have to either use a mouse wheel or arrow keys on a keyboard to scroll through the list. All of the type families in the list are expanded to show all styles in that family by default. That makes the task of scrolling through the fonts list a much longer process.

I recommend only adding/installing Adobe Fonts that are needed at that time. It's very easy to add back type families that have been previously removed. It's arguably as easy, if not more easy, than installing fonts directly in a computer's operating system. Apps like Adobe Illustrator, InDesign, etc can automatically activate missing fonts that are available at Adobe Fonts.