I think things like developing Salesforce extensions, SharePoint features, etc has this sort of "parachute in" property too, where the requirement is specific.

I think things like developing Salesforce extensions, SharePoint features, etc has this sort of "parachute in" property too, where the requirement is specific. It is also well paid. I think things like building marketing websites, landing pages, contact forms, etc is like that too on the lower paid end of the spectrum. I'd caveat that "lots of skill" (ala brain surgeon) is typically not the common denominator -- rather niche skill.