WinDirStat

[TimoVJL]

https://windirstat.net/download.html

Nice tool to check folder sizes.

[John Z]

Yes it is very handy. I have used the portable version for many years.
https://portableapps.com/apps/utilities/windirstat_portable

Also a good site, and as the name implies portableapps can be installed on a USB and run leaving no traces, or very minimal, on the system.

However the most used tool now is SwiftSearch - the speed this has searching a NTFS formatted drive is just astounding.  Open source too.
https://sourceforge.net/projects/swiftsearch/


John Z

[Vortex]

Another file search tool : Everything

Locate files and folders by name instantly.

https://www.voidtools.com/

[TimoVJL]

That Everything works fine and was updated recently.