Vivaldi
FreeA browser built for people who keep a hundred tabs open
A famously dense Chromium browser: tab stacking, split-screen tiling, side panels, plus a built-in mail client, calendar and RSS reader, and an ad blocker. Almost every UI element is customizable. Free and ad-free, but not open source.
Why we picked it
Vivaldi is built for chronic tab hoarders. Tabs stack into named groups, tile two or four across for side-by-side comparison, and can run vertically down the edge. If you routinely have a dozen references open at once, the time this saves is real.
It also folds a mail client, a calendar and an RSS reader into the browser — native features, not extensions. Some people call that bloat; others find it replaces three separate apps. It depends on how you work.
The boundary worth stating: it is not open source. The Chromium core is, and the UI layer's source can be inspected, but the product as a whole is not free software, so we did not award the open-source badge. Its privacy promises rest on company policy and Norwegian data law rather than on code you can audit yourself.
All those features carry a cost, too: the settings panel is genuinely intimidating on first open, and memory use runs higher than its peers. Live with the default layout for a week before you start tuning things one by one.
Why it is here: completely free, no ads, no user-profiling business, and no forced sync account (sync is optional and end-to-end encrypted). A good fit if you treat the browser as a workbench.