Opera also invented full page zooming. Originally, browser zoom would only increase text size - everything else (including images, the actual page layout, etc) would remain the same size. Opera was the first browser to instead zoom into the entire page.

It also had a lot of features that either require extensions or don’t even exist these days. Things like being able to disable JavaScript or change the User-agent per-site, basic content blocking before ad blockers existed (like modern-day ad blockers but you’d manually build your own list of things to block by going into content blocking mode and clicking on them), an option to only show cached images (useful on slow dial up connections), a fully customizable UI (literally every toolbar, button, and status bar segment could be moved around), and many more.

It was truly a web browser for the future, far far ahead of its time. I miss those days.