Can you download or buy new Toolbar Icons to customize each Program or Apps Toolbar?

[iMore Question]

Currently using:
MacBook Pro with OS X El Capitan version 10.11.5 and
Safari version 9.1.1.

It seems that each App or Program has only a select and specific # of icons available to customize with. We are trying to get the "Mark Up" Icon/Toolbar that we use with the Preview App to work over on the Safari Toolbar. I cant figure out a way to make that happen.

The Mark up icon looks like a little toolbox or like Fred Flintstone's lunchbox. It's used to annotate documents or pictures, etc.

Thank you all for anything you may know about this subject!
"Frustrated and wanting to buy an icon!!"

 

[Just_Me_D]

I doubt it, but I'm only speculating. Hopefully, someone who can provide a more definitive answer will reply soon...

 

[anon(9602380)]

Welcome to iMore!

Safari does offer extensions. Have a look at what they have to offer. You may find something close in the Productivity extensions. Unless you develop your own extension, I know of no other way of doing what you are asking.