I find one-shots mighty interesting cards. There are different types in Dominion and I wonder if we will see more of them in future expansions. What is a one-shot? By my definition it's a card that trashes itself when played or gives an added bonus when it trashes itself. Of course nothing gets really trashed when you are Possessed, but that's another story. Let's talk about the one-shots a bit and at the end... speculate.
Feast - The first one-shot we've all come across. It's plain and simple. You buy a $4-card now and when you play it, you get a $5 one. It's for those $5's you absolutely can't live without or have to get asap. Of course it's really fun to King's Court a Feast so you can get three $5 cards (Duchies for instance).
Mining Village - Intrigue gave us Mining Village, an intriguing card for sure. A lot of players wonder when they have to trash it for $2. Even if you KC it, you can only trash it once for those $2, because of the condition on the card. I usually trash these only when I need to grab a key part of my engine or late in the game when I can convert them to VPs. MVs are also often used in the beginning as one-shots to a power $5 or $6 card, much like Moneylender or Baron let you do.
Embargo - One of the most difficult cards to use strategically. They're probably the most fun when your opponent has opened Potion. Embargo games are very weird generally. Ever played a game with 3 tokens on the Province pile? The Embargo does stack with KC so you can place 3 tokens on a pile. With Possession, you can even put an unlimited number of tokens on a pile, but you won't need more than 50 or so (6 player game).
Treasure Map - Half of a Treasure Map, actually. We all love to hate it. Our opponents always get it together on turn 5 without help and all the Warehouses in the world can't find our copies. Still, it's a funky card and the only card that you can trash for absolutely no bonus (other than activating a Conspirator or something). Any of you ever tried to play it to put it back with Scheme? It doesn't work.
Island - Stretching the definition: While Island doesn't trash itself, it does remove itself from your deck and this can be quite handy. It's sometimes good to Island away one Estate in the beginning. If all else fails, you can always Island away a Copper or even a Curse.
Fool's Gold - It stretches the definition a bit too, but I'd still like to include it. Alchemy, Prosperity and Cornucopia offer us no one-shots so we have to make do with what we've got. I'm horrible with FG, but it's one-shot bonus seems pretty clear to me. There's always a big downside to its reaction: Your opponent just bought a Province.
So with 7 boxes we've got 5 one-shots. If we were to see more of them in the future, what would they be like? What would you want them to be like? Do you have any good ideas for a one-shot? Let us know!
Edit: Modified TM, added Island
