Compare Pathfinding to Prince. Pathfinding gives you benefit as early as the next turn depending on what actions you have and doesn't take space in your deck. The ability to turn any cheap cantrip into labs or any action that gives +1 action into a cantrip is pretty good.
A few ideas...
Festival => Grand Market + Village (!); and Festivals are much easier to buy.
Pearl Diver => Laboratory; in Ironwork boards or boards with +buy (Goons), you may end up easily with 7-8 cheap Pearl Divers. Plus, there won't be any competition from your opponent to get them, except if she realizes your intentions. So far, I've yet to see a game where people are fighting over Pearl Divers.