I tend to call anything that doesn't get a village big money. Anything that gets a village is aiming to play 2 terminals a turn instead of 1 and is engine. To me that's usually a pretty clear dichotomy, Villages tend to be a do or don't thing. Gray areas include when crossroads is a good enough village for your BM but repeatable villages aren't, and Walled Village, but Walled Village is dead, and the crossroads thing is rare, so.
That's just how I personally sort the things in my mind. To me Hunting Party stack into Margrave is still Big Money, you just like Hunting party more than Silver.
I know there are probably tweener decks out there, decks that use Journeyman to find treasures unless they have a village in hand so they find more actions instead and stuff like that, but really the 1 terminals or 2 terminals goal has few exceptions.
Big Money decks can almost always green earlier, and with the advent of dark ages I love pressuring engine opponents to start greening with me because my Trader deck or Rabble rouse is ready to handle it