* A good browser - Fennec, Brave, Vandium, etc. Something that works with PWAs while blocking ads and minimizing tracking. Most apps can be replaced with a web version.
* A maps app, Organic Maps or OsmAnd work great
* A media player like VLC if you're switching away from something like Spotify or regularly download audio/video from Youtube
* A notes app. I like Joplin for its sync feature, but other tools like Markor, Notally, and Simple notes are all good.
* An RSS reader, its great for following accounts across platforms and beats out most dedicated apps. Read You + Fresh RSS goes great, but Feeder works great too (& has Nostr article support)
* A YT client like NewPipe or Grayjay if you watch/listen to YT on your device
* Some form of cloud storage/sync - be it Proton Drive, Syncthing, Nextcloud, or something else
* Basic offline tools - equate (unit conversion) tape measure, tasks (to do reminders), trail sense (outdoor oriented tools), pocketpal (local llms), Snapseed (photo editor - by Google but runs offline with no G services needed), TTSutil (text to speech or audio file tool)
* Messaging apps - I use Beeper (for Google chat) and Signal because that's what family uses, it'll vary depending on what you need
* App stores - Aurora, F-Droid, Acresent, Zap Store, Obtanium - take your pick
* Termux or the integrated Linux terminal if you want to run CLI software
* Games, there's plenty of foss games to kill time with. A few recommendations: Anuto TD, SuperTuxKart, Unciv, Endless Sky, Tri Peaks, Solitaire, Domination, emulators.
* An ebook reader (I use Librera) + optionally a TTS engine
* And since we're on Nostr: Nostr clients/tools, proxies (vpns, orbot, Tor Browser, I2P), and/or crypto wallets depending on what you're personally looking for.