For me it’s: Testdisk (and Photorec) Caddy Netstat Dig Aria2
I love programs like freecad despite the really hard/unintuitive gui. 95% of all the modelling i need to do (as an amateur) can be done easily in a python script.
The finishing touches like adding filets and chamfers are the annoying part were gui is easier, due to the way edges are referenced.
Likewise at work, we have to produce a lot of regular reports in excel. All done via python / sql.