I'm curious if there is any jargon/keywords in use here already relating to a topic that I'm researching other people's experiences with, as my own background leads me to use very personal nomenclature for such things.

The concept in question is awareness and modification of the "set of all options I'll think of when presented with a given type of problem". I usually call it "option space" for short when discussing the concept with others, but since it's not exactly an art you can pick up in 15 minutes I haven't met many others who've dabbled in it.