Mozilla Firefox is a popular, extensible, open source (mostly) web browser that is highly configurable and easy to use. Somewhat bare out of the box however, its functionality is easily extended with add-ons, or 'extensions' if you prefer, of which there are many thousands in the Mozilla add-on repository at addons.mozilla.org (AMO).
https://addons.mozilla.org/en-US/firefox/addon/search-engines-helper/
https://addons.mozilla.org/en-US/firefox/addon/mozlz4-edit/