For iOS:
Fully FOSS:
- Organic Maps - Offline Maps
- Yattee - YouTube Frontend
- BookPlayer - Audiobook Reader
- NetNewsWire - RSS Reader
- Signal - Encrypted Messaging
- Element - Matrix Client
- OrBot - Tor VPN Alternative
- Swiftfin - Jellyfin Client
- VLC - Media Player
- Metapho - Remove EXIF Data
- Privacy Blur - Blurring Photos
- Raivo - 2FA
- Firefox Focus - Web Browser
- Mastodon - Official Mastodon Client
- PixelFed - Official PixelFed Client
- Sync - Reddit App (RIP?)
- Mlem - Lemmy App (currently testing)
- KDE Connect - Airdrop Alternative
- Berty - Encrypted Messenger with Offline Capabilities
FOSS, but with a paid tier:
- KeePassium: Offline Password Manager
- Slide for Reddit - Reddit App (RIP)
- AdGuard - Content Blocker
- Bitwarden - Password Manager
- Joplin - Note App
- Podverse - Podcast App
- NextDNS - DNS Filtering
- Invoice Ninja - Invoicing Software
- SimpleLogin - Email Aliasing
- ProtonMail - Encrypted Email
- ProtonCalendar - Encrypted Calendar
- Proton Drive - Encrypted Cloud Storage (Testflight is Full)
- ProtonVPN - VPN
- Standard Notes - Encrypted Notes
- Notesnook - Encrypted Notes
- Tutanota - Encrypted Email & Calendar
Paid Only, but Open Source:
Privacy Friendly, but not FOSS apps:
- QuickScan - Document Scanner
- Hello Weather - Weather App
- MySudo - Phone Number Aliasing
- Mobius Sync - Syncthing Client
- Privacy.com - Virtual Credit Cards
Edit: Added ente Photos, Mullvad, IVPN, Tutanota, Standard Notes, Notesnook, and Berty