Here is short list what it could look like in the simplest form. Also it would be great if there would be information where the app can be get (Chum, Storeman, Github etc.)
Telegram → Yottagram (no video calls) or Fernschreiber (no audio or video calls)
Signal → Whisperfish
Reddit → Quickddit
Youtube → Microtube or Sailpipe
Bitwarden → Bitsailor
Any OTP application → SailOTP
AI chat app → SailorAI
Google maps / HereMaps → Pure maps and/or OSM scout
Bluesky / Mastodon → Multipos or Tooter
Matrix client → Sailftrix or Hydrogen
Now as I tried to look the native apps, I stumbled on this thread List of Android -> Sailfish OS applications. Probably not up to date perfectly but seemed as very good listing!