My favourites so far.

• PlainApp
• Rethink
• Audile (Shazam FOSS)
• Notally
• OpenBoard (keyboard)
• Material Files
• QKSMS
• OsMand~
• Forecastie
• Obtainium
• Newpipe
• Cromite (Bromite fork)
• Monocles translator

Not open-source but the only gallery I found without trackers:

• Gallery made by Greensoft infotech

Catima - for saving arbitrary barcodes and stuff that are hard to integrate into other wallets. I keep my local library card in there, and it works wonderfully

Nonocross - fun little game that has zero frills and distractions. Also very responsive on their github to suggestions and improvements

Termux - when I need to get into things from afar, this is how I do it

Box, Box! - Formula 1 news, schedules, standings, etc

Coffee - Sometimes I want to keep the display awake, so this comes in handy

There's a lot of good recommendations here but I haven't seen anyone recommend Trail Sense yet. I use it to keep track of my steps without worrying about my levels of activity being monitored by anyone else. It also notifies me an hour before sunset since I actually go hiking.

I honestly don't use that much foss on my Android phone, but DVD has to be my favourite. I like sharing memes as videos instead of links in chat apps and it lets me download videos from just about any app or site by just sharing the link to the DVD app. It uses yt-dl in the background, so any site supported by that should work.

We have similar lists, so some considerations:

• Helium314 fork of OpenBoard for keyboard
• Simple Gallery for your gallery (just purchased but there is an emerging fork I'm blanking on the name of)
• Matrix with a Signal bridge so you can use tablets and other devices with Element, which has a wider range of devices
• NeoLauncher is like OL, but with more configuration
• Thunder for Lemmy. Great client, and only one with 2 column tablet support

F-Droid, Voyager, Eternity, Libretube

Material Files - the best files app I've ever used! Clean, material design and has everything I need. It can even run an FTP server

https://text.tchncs.de/czars-blogs/apps-i-use The blog itself is foss software writefreely

Here are some not mentioned in this thread yet.

• App Manager - App manager on steroids
• Calculator++ - Have used this calculator forever
• DiskUsage - Storage analyzer
• J2ME Loader - Emulates old JAVA games
• Jellyfin - Client for Jelyfin media server
• PCAPdroid - Network sniffer
• UnicodePad - UTF char explorer

Nextcloud News I like for RSS since it fetches the full text article. Obtainium lkke others mentioned is a must have for me.

Anyone uses InnerTune?

Obsidian isn't FOSS. I highly recommend Logseq but keep in mind they require CLA signing for contributions

I'd recommend Mull instead of Firefox or Fennec (the deblobbed version) since it's hardened.

It's basically a Librewolf analogue for mobile

Organic Maps, Syncthing and Feeder.

Obtainium is pretty good

Keyboard:

• AnySoftKeyboard good all around keyboard, good language support, decent though messy customizability
• Unexpected keyboard more specialized, provides easy access to app (printable) ASCII characters and some others, allrght customizability
• 8Vim Cool factor, great customizability, decent language support but you need to learn it

Games:

• Pirate Solitare nothing much but I've been playing it a lot lately
• Simon Tathman's Puzzle Collection a cross platform puzzle collection, has a lot of different puzzles in a uniform style
• Antimine minesweeper with nice ui

System:

• RethinkDNS: DoH provider and firewall Easy to use, especially nice for those non FOSS apps you need to have to maintain a social life, not that powerful though
• Obtainium: FOSS app downloader Downloads apps from releases or equivalent, therefore can have faster updates than fdroid, but no discovery, aside from search on some platforms
• ffupdater: FOSS browser downloader Like obtainium, but for browsers (mostly) and has list of browsers
• Droid-ify: fdroid client better ui than the default app, comes with a list of repos
• Shizuku: ADB shell api not useful if you have root (see SUI, which is the root implementation for the same api, though shizuku will also work I think), but can give a bit more access if you don't supports wireless debugging on A12+
• Neolauncher: launcher nice ui but nothing special
• SD Maid SE: storage cleaner okish ui, doesn't stop me from having 302 (not including system) apps on my device. Yes I have a problem
• Package manager: app manager Shizuku support, powerful, though limited if you don't have root
• Inure: app manager [freemium (8$), but GPL licensed?] pretty must like Package manager but with amazing ui

Media:

• LibreTube: Piped (youtube) client Nice ui, no ads, sponsor block support, kinda unstable
• Innertube: YouTube music client doesn't use piped/invidious, no ads, nice ui
• Tusky: mastodon client nice ui, quite stable, multiuser support
• Jerboa: lemmy client ok ui, up to date with lemmy updates
• Liftoff: lemmy client nicer ui then Jerboa but doesn't work since .15 (?) and had issues with rendering markdown properly
• LibreTorrent bitTorrent client for downloading all those isos and public domain works, nice ui

Misc:

• Mull: ff based browser not much to say, "security oriented and deblobbed", upstreams some features from Tor
• Calculator++: A scientific calculator A lot of functionality while remaining easy to use
• RPNcalc: A Reverse Polish Notation calculator best RPN calculator I've found on fdroid, less powerful than Calculator++, but RPN based calculators are more efficient^[citation needed]^
• Simple Apps: suit of apps providing basic functionality great ui and customizability, I don't use simple keyboard, simple launcher/drawer however
• OpenCamera: a camera app advanced features

Just the apps I thought of, as I, as mentioned in the SD Maid entry, have a lot of apps installed :P

Ente Auth is nice for OTPs, it looks nice and I like that it shows the next code in case it's about to switch.

Neo Store for browsing fdroid

Moshidon for Mastodon

Seriously guys, no one saying Nextcloud?

• The main app for photo backup.
• Nextcloud Notes for well, notes you can also use from the desktop.
• NC Passwords for well, passwords
• Phonetrack to record your phone to Nextcloud Maps.
• Deck for the Kanban.

2FAS, Bitwarden, Firefox are my most used FOSS on Android for me.

OpenBoard + predictive text binary

What's FNG? Fluid navigation gestures? Is that FOSS? Can you share a link to the codebase? Can't find it