Another tricky thing is defining "behind" in Dominion. You could define it as having fewer points, but it's also easy to say that a deck with 8 Estates and not much else is "behind" a deck that has 0 VP but a bunch of King's Courts and Laboratories and Bridges.
If it's a question of how far along your engine is, then
Quarry could be considered a card that is better when you are behind; because once your Engine is fully up and running, you don't need Quarry anymore. Similarly,
Chapel is better when you are behind in trashing stuff; a player who has already gotten rid of their junk doesn't need Chapel.
I suppose trashing attacks are the closest thing Dominion has to a pure "catch-up" mechanism. Similar to what was said before about Masquerade; trashing cards from the ahead player's deck will hurt more than trashing cards from the behind player's deck; or bring both decks into more equal footing. The problem is that a good "ahead deck" can play more trashing attacks per turn than the other player.
The old KC+Goons+Masquerade pin was really the ultimate "catch-up" mechanism in Dominion; it didn't matter how far ahead one player was in terms of points or engine functionality; if the other player got the pin; the other player catches up and wins. But again, how to define "ahead" in this case; it could be easily argued that the player who had KC+Goons+Masq in their deck really was ahead of the other player, because they were closer to pulling off the pin.