I know this thread has mostly been used for free video editors, but there is more to fan editing than just cutting video. Starting with basics and then getting more advanced as we go...
Fan Edit Basics
Makemkv - Blu Ray disc ripping tool
TsMuxer - video and audio stream extraction tool for Blu Ray rips.
Handbrake - video conversion tool (for final delivery format after editing)
Davinci Resolve - free video editing, as others mentioned
Audio
Cakewalk - pro grade music making software, went open source a few years ago.
Audacity - open source audio editor
Spitfire Labs and BBC Orchestra - VST orchestra instruments released for free officially (make music)
BBC Sound Effects - sound effects released officially
Freesound.org - open source sound effect database
Incompetech, soundly - free to use music
PaulStretch - extreme audio stretching without losing pitch.
VFX
GIMP, Photopea, and others - Photoshop alternatives
EB Synth - style transfer tool for video (add visual fx)
Boris FX Particle Illusion standalone - powerful particle emitter tool (add visual fx)
Blender - open source 3d program with game engine, video editor, 2d and 3d animation, modeling and rigging and texturing capabilities, and a lot more (add visual fx, create scenes from scratch, use as video editor?)
Unreal Engine - it's free, they use it to make The Mandalorian. Try it?
AI Tools
Spleeter, lalal.ai, Vocalremover.org - AI voice removal, search around also for similar services, most are new and free.
Remini - Android app that upscales and attempts to add detail to human faces (use in conjunction with other software to upscale deleted scenes?)
Rife - generate new frames to create slow motion or high frame rate.
misc resources
Unsplash.com - free to use photos
productioncrate.com - they do sell stuff but ignore that. sign up for an account and get 5 free downloads a day, the site is split up into footage, VFX elements, sound fx, music, etc. the free stuff is useful, just go back a few days in a row to get more than the initial 5, the download limit won't roll over, it resets each day. Warning, even just looking through the free stuff, this site is a deep rabbit hole.
I'll come back and add links when I have time, and will probably add more to the list as more comes to mind. Google will help until then.
Edit: added more free tools to the list, no links though