7zip (open any archive)
VLC (open any audio/video file)
IrfanView (+ the "all plugins" installer on the same page, open any picture file)
SumatraPDF (read PDFs)
Libreoffice (to open any office files)
NAPS2 (easy scan, and split/merge/... PDFs)
Ditto (give your clipboard a memory)
Everything (an instant file search that works)
TeraCopy (replace windows copy with queue, queues, add files to the queue instead of starting a second parallel copy, pause that works, ...)
Powertoys (so many to list ... mass rename file easily, screen ruler, text extractor ...)
If it's appropriate : Qbittorent (clean torrent client)
Nvidia graphic card ? NVCleaninstall, so you can install just the clean driver you need
Windows 10 or 11 ? O&O Shut Up (to disable all the telemetry and onedrive in one click, there are plenty alternatives but I sort of like this one)
Windows 11 ? ExplorerPatcher to remove suggestions in the start menu and the new and terrible castrated contextual menu
And of course your browser of choice and extensions
In ten minutes you have a computer that feels much more smart and usable. There are plenty of great software out there, but I feel like many what to install lists are very topical or include software you won't use in many cases or once every 6 months, so this is my short list of what you will use essentially every time you use the computer.
TreeSize (to easily find out what is consuming disk space)
picpick/ shareX (screenshotting with annotationsand autosave)
pdftk (pdf merge, split, crop, interleave(
ffmpeg (video trim, split, re-encode, etc.)
Lossless cut (GUI for ffmpeg trim and extract/add tracks)
OpenShot video editor (when DaVinci Resolve is too much for the job and you need simple edits and effects)
OBS Studio (screen record, stream to youtube)
WinDirStat (which used to be my goto) took over 6 minutes and ate 625mb of ram.
TreeSize Free took over 30 seconds, I'm not sure how much ram as it doesn't report it. It also kept trying to upsell me.
WizTree took less than 8 seconds. What's wrong with it?
edit: 2tb nvme ssd, mostly full of rubbish, windows 10.