Looks like you started a 'sleeper' thread!
I (myself and guys who worked for me) fabricated a few things over the years, nothing in any quantity, just what we needed & couldn't 'get' quick or affordable.
Racking for mounting transformers on walls; basic 'L' steel angle, measure, cut, fit & weld. A couple of brackets for the Greenlee tugger for specific jobs. A few cross-arms for lighting installs, etc.
Nothing like you describe within, just some basics.