Try : https://mozilla.github.io/extension-finder/ No idea about mini-tabs but https://www.howtogeek.com/333110/how-to-customize-firefox-quantum-and-remove-the-white-space-around-the-title-bar/ Here's a more comprehensive project which affects not only tabs but brings back the old "grid-style" options menu. https://github.com/axydavid/FirefoxUI/blob/master/README.md It isn't completely possible to use the Australis design with Firefox 57, but depending on what you want, you might be able to customize the UI to look more like the old one: This project: https://github.com/wilfredwee/photon-australis lets you have the old tab bar appearance back in Firefox 57. You can remove the space around the address bar by right-clicking on the spaces, and choosing "remove from toolbar". Note the Black Theme is just a Example and can be found in Customize. More code will be coming, check github from the above URL for what you are looking for. Please let us know if this solved your issue or if need further assistance.

A WE version of Colorful Tabs is available as of Nov 17 - version 32.0, with 32.1 being available on the 20th. https://addons.mozilla.org/en-US/firefox/addon/colorfultabs/ Check the "versions" page to see which Version work with which version of Firefox. https://addons.mozilla.org/en-US/firefox/addon/colorfultabs/versions/