Replace Office 365 O365_MainLink

https://collab365.community/changing-the-office-365-main-link-text/

https://social.msdn.microsoft.com/Forums/en-US/bc46c008-1053-41be-952a-aeda88e7b69a/new-app-launcher-suite-bar-in-365-what-css-styles-affect-the-background-color

https://social.technet.microsoft.com/Forums/en-US/4e27ba4c-fbcf-43b2-80eb-d2d6f0a48392/style-edits-to-master-page-on-team-sites

Stylebot

https://chrome.google.com/webstore/detail/stylebot/oiaejidbmkiecgbjeifoejpgmdaleoha/related

User JavaScript and CSS

https://chrome.google.com/webstore/detail/user-javascript-and-css/nbhcbdghjpllgmfilhnhkllmkecfmpld

Styler

https://chrome.google.com/webstore/detail/styler/bogdgcfoocbajfkjjolkmcdcnnellpkb/related

https://www.awwwards.com/15-great-chrome-extensions-for-web-designers-and-developers.html