Tell me what, to you, are the gold standards in terms of app replacements and just privacy focused apps in general. I am going to leave my list here but of course everything is subjective. I'd like to provide reasoning for my choices and I hope to see the same. I made this list just because I saw that there are some shaky recommendations going around and I'm not really a fan of some suggestions.

Gallery: ReFra is an obvious choice, a lot of support, great integration, and probable official GrapheneOS app from what I've heard.
2FAS Auth, Ente or Aegis are probably the best authenticators for most people. It's good that Ente supports plain text export for secret keys for printing. 2FAS does not but it looks like a deliberate choice.
addy.io for Aliasing. I haven't tried SimpleLogin, but I've read up on Trustpilot reviews and it seems to me like I did a solid in choosing Addy over Proton. They should both work fine though. May come down to customer support quality.
Bitwarden is, to me, the best choice for a password manager.
Brave Browser and Tor have been my browser choices. Tor is Tor but Brave, considering how well it blocks ads, trackers and pop-ups, it is very nice that it doesn't break sites, and strikes a good balance for me. I've tried Mullvad but not a fan. Chromium browsers are best for most people regardless.
CalcYou is a good calculator app with a minimalistic design but it's not a big deal to differentiate these. Any offline calculator will do.
Contacts, Calendar, Phone and Messages from Fossify are nice, but I'm not the biggest fan and I just keep using the stock apps with Proton Calendar on the side which I enjoy more.
CoMaps for navigation has to be the best open source navigation app out there. I have tried them all (Magic Earth, OsmAnd, etc.) and it is literally night and day. It's even better than Organic Maps which it forks off from.
I still use Google Maps from time to time. Where I live it's just too convenient for finding specific places, restaurants, menus, etc. but for navigation CoMaps is the only thing I need.
EasyNotes from Accrescent to me is a very solid and simple choice for local note-taking. I don't need syncronization for those so people may know better options.
Ente Photos: probably the best app for cloud photos as there aren't many choices but Immich is great if you're self hosting. If you use Ente Photos you should not login into your Ente account on Ente Authenticator.
Heliboard is probably the nicest keyboard app I've found and I've tried a bunch. Not much to elaborate on but I like the fact you can import swipe typing into it and the level of customization it has.
Gadgetbridge is probably the only app for connecting devices in the most privacy-friendly way, to my knowledge.
Grayjay and NewPipe / PipePipe: I like Grayjay because it can cast to my Chromecast, which I haven't thrown away for some reason, but still find it useful. PipePipe is great because it's super light but I do agree on the concerns the NewPipe folks have with SponsorBlock. Sometimes I do appreciate it but sometimes it's just annoying what the community deems "unnecessary" in a YouTube's video.
Music (I will encompass everything here): there are many apps out there but so far this is my list:
- Metrolist for YT Music stuff
- SpotiFLAC for downloads
- Symphony for offline music
I downloaded all my Spotify playlists and am about to pull the plug on that.
PDF handling: I have struggled to find a good PDF app where I can apply a signature, and I don't really like XODO to be honest. I've settled on Foxit for signing and viewing PDFs with Network restricted. Also, OSS Document scanner is good for scanning documents.
Proton. Now, your level of using Proton may vary, but for my uses, I've found the Drive Plus subscription the best thing for me because...
I use Proton Mail (free) but don't really need anything extra apart from the storage, which is good because Drive Plus gives you shared storage between Proton services.
I use its Drive as I am not self-hosting. I also use the rudimentary Photos section in Drive to store a secondary backup of my photos from Ente.
I also use Proton VPN free (as a guest) as that's all I need and only care about masking my traffic from my ISP. It breaks PipePipe sometimes but it's not a big deal to me as I am very sealed out from any predatory service like Google. But I agree that a service like Mullvad VPN is just as good as paid Proton VPN.
Signal or Molly also good choices for your privacy but that's less of a choice and more how much you can convince people to migrate from Whatsapp and Telegram, etc.
I almost didn't include this section.
TranslateYou is a great app for translation with minimalistic design.
Tuta Mail: I also have a Tuta Mail free account as a backup email. But I am still deciding what to do with it.
Weather: Breezy Weather is a great choice for me. Not only for its minimalistic design but because it can also sync with my Pine Time smartwatch through Gadgetbridge.

Honorable mentions: Pixel camera used offline, Google Photos as an offline editor app. LibreOffice apps for viewing documents.

Side note, if anyone is concerned about the fact I use Proton Drive:
It's fairly easy to set up a standard fall back system like...

Portable SSD with Proton Drive contents and authenticator secret key backup file and recovery codes for various services;
Spinning HDD or second SSD with Proton Drive contents and authenticator secret key backup file and recovery codes for various services;
USB Flash Drive with authenticator secret key backup file and recovery codes for various services;
Printed sheets with Bitwarden's master password and its 2FA reset code in various physical spots.