Search for ALL large files and folders (not just some) using Finder (not third-party)
It's possible to search by size using Terminal (Confirmed working on Mojave). 

No 3rd party tools or hacks.

Here is a command I used to look through and find largest folders taking my space away (run as root and the command to switch to root is: sudo -i):

du -k / | awk '$1 &gt; 500000' | sort -nr


Once you get the list (ignore the 'Operation not permitted' since those are files you can't (shouldn't) mess with anyway) and look for the top ones.