Tools for design engineers

What is the best tool for mechanical design engineers?

This question is far too broad to get a simple answer.

For many the best tool for mechanical engineering is a $100,000.00 specialty workstation with specialty 3d software. For many it’s a FLOSS (free libre open source software) package that runs on simple generic PC software. I’ve seen good and bad designs from mechanical engineers who used each option and many options in between.

My experience over the last 40 years has taught me that the best tool is between your ears and requires a lot of work to get it up to speed (IME this applies for all of the engineering and science disciplines). Once that tool is well formed then it’s much easier to find additional tools that help increase the speed and/or accuracy of your designs.