Hoard is strong. Very strong. So strong, in fact, that when Hoards are present, you usually don’t need to buy Gold if you can just draw your Hoard often enough. And you really don’t need more than one or two; with Hoard, your deck will be quite a bit stronger than it usually is after the VP-buying starts. This means that with $6, you can start buying Duchies much earlier than you normally would.
Hoard is most powerful with the mixed Victory cards (Great Hall, Island, Nobles, and Harem). It’s also a great way to run a Duke/Duchy strategy, since picking up a couple Hoards before buying the Duchies and Dukes is usually enough to keep your deck producing $5 even after you saturate it with Victory cards. The same principle applies to Gardens strategies, though you should keep in mind that most Gardens strategies depend on fast endings, and building up to $6 for the Hoard might be too slow.
Hoard is also the rare card that benefits from a ton of extra Buys, especially with the Bridge. And Watchtower can turn this into a devastating combo: stack up on free Estates, optionally trashing them as they come in, while top-decking your Golds. Add in a Herbalist for further ridiculousness.
In general, if there isn’t another viable buy, then you should always try to use Hoard to buy a Victory card, even if that means buying an Estate or Duchy before your first Province. This is especially true when there are trashing cards available, and even more true when those trashing cards provide benefits. Salvager works best with Hoard, since it gives you a +Buy for all those Golds, but Apprentice and Bishop are almost as good.
So when would you pass up Hoard for Gold? Well, Hoard naturally works very badly with Treasury. Hoards are also less effective when Platinums are available; cutting out the Hoard and bootstrapping from Gold to Platinum can get you to Colonies faster, since it’s difficult to get to Colonies with just Hoarded Golds. And there’s not too much point to Hoards late in the game; for instance, if you have Royal Seal or Watchtower, you might choose to buy and top-deck a late Gold rather than a Hoard, so that you can get to the last Province/Colony sooner.
- Great Hall, Island, Nobles, Harem
- Salvager / other trashing cards that provide benefits (Bishop, Apprentice) (sample game with Bishop)
- Duke/Duchy or lategame Gardens strategies (sample game)
- +Buy, especially Bridge
- Explorer, which encourages early Province buying
- Mine, which can convert late-game Hoards into more useful Golds or Harems
- Mint, since you’ll have a plethora of good Treasure to duplicate (sample game)
- Strategies that depend on few Treasure (Minion, for instance)