Chariot Race + Secret Passage
Chariot Race has so much potential to be a fantastic source of VP: cheap, peddler-variant, and easily spammable, but its randomness makes it unreliable--paying $3 for what are often just plain cantrips half the time isn't so great. There basically are two primary ways to make Chariot Race activate more consistently: A) have a higher average value deck than your opponent, or B) control what's on top of your deck.
Secret Passage is tailor-made for controlling the top of your deck and activating your Chariot Races. With Chariot Race in hand, playing Secret Passage allows you to drop the most expensive card in your hand on top, like a $5, a Gold, or a Province, to vastly increase your chances of getting the coin and VP. Even better, you're happy buying lots of both cards since they're both non-terminal, and each pair can practically guarantee each of your Chariot Races are enabled. I played game the other day where a single Gold was my expensive card that I could repeatedly drop back on top with each of my Secret Passages and redraw with each of my Chariot Races, generating 5-7 VP every single turn thereafter. With another strong terminal attack to slow your opponent down (in my game it was Ghost Ship), you can pile the Secret Passages and Chariot Races and then theoretically earn points almost infinitely without ever greening.