The best alternatives to CSS Inspector are CSS Scan, Toybox, and QuickLens. If these 3 options don't work for you, we've listed a few more alternatives below.
Collect visual feedback from your team and clients directly on your site. Toybox is the fastest way to create, collaborate and manage ideas on any website.
designr is an open-source browser extension designed to inspect and save CSS styling on web pages. designr provides information about element styles and save the styles into a palette for later use.