An anti-synergy within the Loot pile: Sword makes Puzzle Box's ability a lot less useful.
Exactly the opposite many times. Puzzle box is vastly better when your opponent has Sword because you can topdeck Shield (or Moat or any of the dozens of other Sword counters should they be in the kingdom). Being able to top deck the appropriate reaction (be it Shield or Wt) is much more clutch when dealing with painful discarding attacks.
Abundance plays really poorly with Night gainers like Vampire
Works wonderfully with Cobbler. Gain and play, buy an action, get the coins. It makes a good target to gain with Dw. Changeling has downright synergy (buy a useless $3 to activate a few Abundances, gain an action to activate, return it for a Changeling, use that next turn for another abundance). Even Vamp is not that bad as any viable $3 (e.g. Village or Moat equivalents) can be paired up with a complementary $5 gain. And, of course, +buys are exceedingly handy on Vamp boards if you want to keep gaining through the late game. I mean, yes, you cannot stack them for later but in Vamp games you rarely need to stack them and instead should be using them as renewable Stockpiles.
NMF:
Inherited Royal Blacksmith - People don't buy this early for a reason. Watch out for misclicks.
No this is obnoxiously good. You just elect not to play it until you have some better cards, Literally completely 100% better than estate outside of the universal exceptions (e.g. Baron/Estate). The real bum option is Inherited Castles. Small castle brings your average card to $0.8 wonderful. Crumbling castle is NOT gained so you neither gain the silver (so your average cards is still $0.7) nor the VP point (so it literally starts at the same value as the estate it replaced).
Patient Swamp Shacks - Can actually be extremely useful with Prepare or Journey. But nothing to make you curse your deck order like seeing the option to play a dead card for little effect next turn.
Any sort of duration setup is quite useful as well. And even a Patient ruined village can be quite nice from time to time. I have done quite well with Astrolabes, for instance. Changeling has the same constraints with the added detriment that delayed play trashes the card for nothing barring the outs and can always be played during the Night if you can set it aside during cleanup.
Tireless Hireling etc.- Tireless can be meaningless. I really wanted to think of an anti-synergy - a card you want evenly spaced in your deck rather than clumped together (e.g. Throne Room and King's Court). But there's a lot of ways those cards benefit too. So useless Tireless it is.
I would suggest Shepherd. With a green deck, the end up clumped, not in your hand. Going with one or two to avoid clumping can be helpful, but only if you have green in hand when you draw it.