Borderless Chameleon Theme v1.14
Inspiration from Chameleon Dynamic Theme by Lin Onetwo and Huy Tran which is a fork of. It adds the extra colors from the Borderless White and Borderless Dark themes.
Unlike other themes this one changes tab background separator, toolbar field separator, toolbar top separator, toolbar vertical separator making things look more flat. It also simplifies the toolbar and sidebar.
Also compared with other forks it does not change the new tab theme for about:newtab and about:blank. This makes it change the color less often and you see less blips of color.
The extension I forked is here https://addons.mozilla.org/en-US/firefox/addon/chameleon-dynamic-theme-forked/