These free apps are my favourites, there are many more. They have all recently been updated. Only Handbrake has a Universal Apple Silicon version at present, though I am sure that will soon change and in any case all these apps should work well under Rosetta 2 on Apple Silicon. Some apps have a paid for variant, or request contributions – I’ll leave that up to you. The free versions all work fine as of December 2020.
These links should take you directly to the Download page, if possible.
Find Any File – better than Spotlight
The Unarchiver – File Opener and Decoder
Audacity – Audio Editor and Encoder
XLD – Audio Decoder and CD Maker
Libre Office – Replaces Microsoft Word
Mactracker – Mac Computer Specifications
Onyx – Mac Maintenance and Hidden Preferences
DaVinci Resolve – Professional Film Editing