MacOS – Restoring icons in finder toolbar

If you use CandyBar, you can change the icons for system folders. Selecting a monochrome set of icons will make all the finder icons monochrome. Note that you cannot change the icons for applications from the App store without breaking their code signature, and thus their ability to update.

You can find the sidebar icons and most of the other icons to which you refer in the folder /System/Library/CoreServices/CoreTypes.bundle/Contents/Resources

If one doesn't mind mucking about in system folders (something one should do with a great deal of caution), one might duplicate some of the Sidebar* icons and use them to replace the corresponding icons without the word Sidebar before them. I wouldn't try this without a bootable backup in place, however, in case I messed something up badly.

If you change your "arrange by" options via "right click" > "arrange by" to any other than "none" spaces between the icons is clinched/stretched according to window size, or icons even get rearranged to the next line if space gets to narrow.

This should be default behaviour without "arrange by" since it kind of breaks list view if active. Sadly Apple rarely listens to customer needs, since they "know what the customer wants".