So let's be really optimistic here and assume this will do the trick:
Let's try to keep this thread on-topic, please In that vein, I'll post a few more of these. Some are classics, but maybe not all of them.
Quarry/Talisman: Relatively well-known, but the big bummer about Talisman is that it can't gain $5+ cards, and Quarry fixes that. Sure, other cost reduction works for this, but Quarry is also a treasure, stacks easily for Actions, and lets you get $6 cards too.
Menagerie/Warehouse: Menagerie is enabled strongly by cards that allow you to discard selectively from your hand, but Warehouse gets a special mention because it's much, much better than other cards for enabling Menagerie decks. You can draw most of your deck without Copper trashing, you can green heavily and not really stall all that much, which are things you're hard-pressed to do with other discarders.