There have been a few good suggestions already (leather working, knife / tool sharpening) for sideline work. Have you thought about a trade that allows you to be your own boss? My landscaper does the whole thing himself. Well, his son just started helping him, but up until a few weeks ago it was just him. No crew of illegals to worry about, just a riding mower an edger and a leaf blower. Same thing for the mobile dog groomer that comes to a number of houses in my area. It's one guy who slowly built up enough clients until he could quit his 'regular' job.