Opera also invented the browser Speed Dial, which was super handy back in the day.

But most importantly, Opera invented tabs, or at least the concept of tabbed browsing. I recall using Opera on Windows 3.11 and for the longest time, even during the Win 9x era, no other app used tabs.

In addition to mouse gestures, they had customisable keyboard shortcuts for practically every browser feature, again, something which very few apps bothered with.

The page compression built into Opera Mini was a life saver on Symbian and Windows Mobile devices back in the 2G/GPRS era. Opera Mini loaded pages blindingly quick and there was nothing else like it on the market, even leading up to early Android days.

but thankfully he started Vivaldi which feels like the spiritual successor.

Too bad he made the unfortunate decision of going with the Chromium engine instead of Gecko, or even making their own engine. I would've loved to use Vivalidi if it weren't for that fact.