Firefox, mostly because I use mobile browsers so infrequently that the choice makes almost no difference to me (So I use what I use on desktop). Having μBlock Origin is nice too. There are a few things that annoy me about it, like not remembering which sites I set to view in Desktop mode, but overall it works fine for what I need.

Firefox + NoScript

No ads and privacy. I don't need more reasons or special features

I'm using Firefox Beta, it's always my default with Ublock Origin. I used to have Firefox Nightly for the pull down to refresh option but it was buggy when scrolling up.
I also tried Vivaldi and Samsung Browser with bottom tab bar, I feel way more productive there, wish firefox had this option too.

Firefox

Three browsers. Compartmentalization. Mull, Fennec, Mulch. First for everyday browsing, second for government, spyware services, third if second is too restrictive for some sites with blocking trackers.

I love Firefox, but I can't live without Chrome's tab grouping. I just don't understand why Mozilla don't add this to Firefox.

Kiwi with uBlock, SponsorBlock & Violentmonkey

Iceraven.

I use Samsung Internet Browser. I like being able to have my tab bar, and address bar at the bottom of the screen. It has dark mode for all web pages, it also gives me the option to use my system font for the web pages. Has ad blockers that you can install, so I never see any ads.

Vivaldi. It has support for bottom navigation bar.

Firefox and Vivaldi. Both have ad blockers and bottom address bar. With Firefox I use some additional add-ons, like Consent-o-Matic, but the Vivaldi interface is nicer and very customizable. I also use the DDG browser for occasional searches.

Until a year ago, I was using Firefox. I made the switch to Brave, because I wanted the Chromium functionality ( I still think Chromium is designed perfectly to use on mobile. ) but I didn't want any ads ruining it.

But, that might change, I heard about Kiwi here, I'll definitely take a look, extension support with Chromium functionality, that sounds too good to be true. Definitely will try.

Edit: Definitely try it, you will love it. It's not just Chrome with extensions. It also has some features you are missing on mobile, like DevTools. It has Chrome's own 'ad blocker', may not be effective but I downloaded Ublock, which gets the job done. Super, super cool.

I was using Samsung Internet but stopped because it simply does not work with Bitwarden's auto fill. Moved to Firefox but it is comically slow, takes at least 10 seconds to load any page. I'm now trying Vivaldi and so far I have no immediate complaints.

Firefox for general browsing. Firefox Focus when I want privacy (it can help get around some paywalled news sources.) If I need to use a Chrome based browser, I use Samsung with an ad block.

Mull.

Because fuck their digital nosiness

Ecosia for me. I keep important internet usage off of my phone and I am by no means power user, so "functional", "unobtrusive", and "does a small good thing" was basically everything I could ask for

Opera/Opera GX, just for My Flow - a feature allowing easy file and text transfer between PC and mobile, functioning somewhat like a WhatsApp DM.

Vivaldi, for sync between desktop and mobile, blocking ads and trackers, notes feature, and interface customization.

Both on phone and desktop I use Firefox and Edge (for different things, most work).

Firefox because it has uBlock Origin built in.

Vivaldi. Fast, respects privacy, sync across devices, UI that matches website colour, tons of customisation options.

Mull

I use Opera GX because of their unique gesture navigation. If Firefox or a fork of it had something similar, I'd probably switch over though.

Cromite (one of the bromite devs forked it from bromite)

Up until two years ago, my go to browser was Iceraven & sometimes Firefox. But then I came across Kiwi (chromium browser with extension support).

For me Kiwi gives the best page loading speeds, compared to Firefox & iceraven & the difference is very much noticeable. I've turned off all the default data collection in kiwi if that matters.

Soul browser for the gesture

Firefox Focus is the default browser, so that any app that launches a surprise browser on me gets its information thrown away when the browser is closed.

Firefox for general browsing. It's sync'd with my laptop and desktop (which is just a really big laptop). It has my Add-Ons installed including uBlock and some other anti-trackers.

I've used Firefox/Mozilla for many decades and generally trust the organization.

uazo's Bromite fork

Brave.

I use Samsung Internet Browser since that Firefox removed the tab bar.