Aside from the routine hammer, cordless drill, screw drivers, etc there have been a few “specialty tools” that I have found invaluable.
In first place has to be the Prusa i3 Printer that I bought in kit form just for this project. After two-day build and a bit of a learning curve it’s been a fantastic addition.
Second place goes to the Fusion 360 CAD program which has been surprisingly easy to learn and use. I have used it to design several parts from scratch, modified others and closely inspect (inside and out) various PacificMeister provided build files.
Third up is my cheap digital caliper which I have used countless times to precisely measure all manner of things related to this project.
And finally are my set of hex (allen) t-handle wrenches used to drive the countless hex screws on my build. Infinitely better than those L-shaped allen wrenches.
I need to try this program. I have been using PrusaControl which is super easy but pretty basic. My 3D printer also came with Slic3r PE which I assume is similar to the Cura version. Being new to the world of 3D printing I know next to nothing about the software end of things.
To contribute to the overall discussion: I can very much underline the things you mentioned, especially 3D printer and digital caliper are indispensable.
Additionally I found my cordless drill and dremel multitool to be very valuable, I don’t have a work shop or garage or any more machinery than these two things, I do everything in my small office room. So far it’s working out fine, but I build a direct drive where the motor unit is much less complex and demanding. Specific to the direct drive I think a circlip plier is essential for disassembling the motor.