Papyrus EX
Notes simply saved as .txt files. No cloud, no fomatation, just simple text.
Notes can be sorted by folders.
As it is just folders and text files, the backup is extremely simple.
Migration to new instalation of the app is just copy to the folder.
It is a ‘back to whats needed’ app.
Blokada
Good ad- and social media blocker for unrooted phones as it is working as a VPN.
Filter lists can be added.
Okay, so, I’m not going to go and name my favourite launcher (Kiss Launcher), favourite IM app, etc. Just the stuff that I think can actually be genuinely useful for people:
First of, I really love FairEmail. It’s Open Source, free (but with some one-time-payment pro-features), fast, responsive and way better than K-9 Mail (which I used for many years). It’s honestly the best Android mail client I’ve ever used.
I also use Password Store, also Open Source and free, as password manager. I wouldn’t recommend it for less technical people, but if you want a password manager that you can sync with your own server over Git with 2FA support, it’s great. I’m obviously very biased here though because I have my own desktop app called Pext that integrates with the same standard that Password Store uses, so it’s my only way of nicely syncing my passwords between computer and phone.
Last but definitely not least: Loyalty Card Keychain. Keeps me from having to use an app for every single company with a loyalty card. I’ve also been enjoying contributing to it in my spare time, so the next version will have a lot of new stuff. So, yeah, slightly biased because my own patches are in the development version of this app, but also just loving it genuinely.
Just a quick info, K-9 Mail just got a big overhaul to a much more modern layout! But both K-9 and FairEmail are good options.
In addition to the original question: Also check out the Simple Mobile Tools-collection, which aims to replace some of the most basic apps on your phone (gallery, file browser, contacts, calculator etc) with a FLOSS alternative.
And I should add Island (probably shelter as well, but didn’t try it) for the really problematic apps…
I have problems with QKSMS. Sometimes after receiving a notification the message disappears from the list, so I can’t read the message again.
After installing SMSdroid the messages that were missing are all there.
(SMSdroid has a very very simple layout.)
Interesting. It didn’t happen to me yet, but I will keep an eye on it.
I wrote SilentNotes, a note taking app respecting the users privacy, exactly for those reasons you mentioned. The app is open source and can share notes end-to-end encrypted between Android and Windows devices.
I needed a note taking app for myself and then it occured to me that as developers we have some responsibility to offer simple alternatives, to the bigger but data collecting apps. At least those who care should have a choice.
Same here. Not very often though
I can always find them in the AOSP messaging app. I even wondered if it had something to do with the fact that I haven’t deactivated it.
I use Brave for browsing and ruff for notes on the go. Otherwise, I am quite happy with Google’s apps, but let them share as little data as possible.
I want to mention AlternativeTo*. It’s a website where you can get alternatives to any kind of software you like. Just search for the program/app you want to replace and it lists you up to dozens (only in a few cases, but still) of more-or-less-similar alternatives. You can also filter for only Open Source programs.
I’ve used the website for a couple of years now and I’ve found great stuff there, e.g. my current email provider 
(*I know, it’s a missed opportunity, since they could’ve bought alternative.to but went with alternativeto.net instead…)
That is a really useful website. I can also recommend “No more Google”, another option to find alternatives to Google apps or services 
Cool, I didn’t know that one yet.
There is also:
Thank you all for your great input! Pure gold Very inspiring - and a lot to try out
For some languages (not the ones you mentioned), DeepL could work
In general, I recommend to have a look at F-Droid first.
For browser, I use Firefox Preview instead of Google Chrome / DuckDuckGo.
For e-mail, I use p=p instead of k-9 as it has material design interface and opportunistic encryption. I also liked FairEmail.
For 2FA, Aegis or andOTP.
For password manager, Bitwarden.
For SMS, Signal also just works.
My favourite application though is NewPipe as it allows one to play YouTube in the background. Ridiculous that such is a paid option. Can’t think of a more appropriate example of a feature which should be a non-feature.
I clicked on that topic from the Summary e-mail just to mention those app. Go! Use them!
For SMS (and MMS) I’ve stopped using Google’s Messenger app a while ago and today I saw that Pulse SMS is now open-source:
The code is here:
Hi,
I would juste like to mention that my fp3 has been crashing non stop since I got Nova running. Actually it just got worst and worst. It might not be suited for the last system updates… Don’t know. Anyway I enjoy surfing on the Brave application, it saves a lot of time and data thanks to the Adblock function.
I’m running nova since the beginning without problems