I have been playing around with GPT-3 to see what it is capable of. I have been working on changing prompts to see what I can get it to do. (I still can't get it to rhyme very well. I think it might be impossible given how it was built).
Here are some Dominion cards I had it create after using a very long prompt with lots of example cards:
Hex $4
Action
Reveal the top 3 cards of your deck. For each Curse revealed, gain a Curse. For each Treasure revealed, gain a Treasure. Put the revealed cards back on your deck in any order.
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Throne $5
Action
+1 Card
+1 Action
Return a card from your discard pile to your hand.
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Dragon $6
Treasure
+4 Coins
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Kingdom $4
Action
+2 Coins
Trash a card from your hand.
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Governor $4
Action/Duration
+1 Card
+1 Action
+1 Buy
At the start of your turn, you may discard a card. If you do, +1 Card.
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Ballad $3
Action
+1 Card
+1 Action
Draw until you have 4 cards in hand.
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Matriarch $4
Action
+1 Card
+2 Actions
Reveal the top card of your deck. If it's an Action card, play it. Otherwise, put it back on top of your deck.
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Ruin $2
Action
Trash a card in your hand. If it costs $4 or more, +1 Card.
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Oracle $3
Action/Reaction
+2 Cards
When you gain a card, you may reveal this from your hand and discard it. If you do, choose one: +1 Action; or +2 Coins.
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Hoard $5
Treasure
When you play this, gain a Treasure card costing up to $4 more than it.
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Consulate $5
Action
Gain a Gold onto your deck. You may play an Action card from your hand
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The Fool $3
Action
+1 Buy
+$2
You may trash this for +3 Cards.
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Skeleton Key $4
Action/Duration
This card stays in play.
While this is in play, when another player plays an Action card, you may discard this card to cancel the Action.
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Robber $4
Action/Attack
+1 Card
+1 Action
All players look through their discard piles and trash a treasure. If they do, they gain a curse
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Court $7
Action
Choose one: +3 Cards; or +4 Actions; or put all cards in play back into your hand
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Deliverance $2
Action
+1 Card
+1 Action
Reveal the top card of your deck. If it's an Attack card, put it into your hand. Otherwise, put it back on top of your deck.
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Viscount $6
Action/Victory
+2 Cards
+1 Buy
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3 VP
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Scout $5
Action
+1 Card
+1 Action
Look at the top 4 cards of your deck. You may reveal an Action card from them and put it into your hand. Put the rest back on top in any order.
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Genie $6
Action/Attack/Duration
+1 Action
+1 Card
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While this is in play, other players can't play Attack cards.
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Dryad $2
Action
+1 Card
+1 Action
Look at the top card of your deck. You may put it on the bottom of your deck.
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Siren $3
Action
+1 Card
+1 Action
You may play a card from your hand.
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Army $6
Action/Attack
+3 Cards
Each other player reveals the top 2 cards of their deck, trashes one of them that they choose, and discards the rest.
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Town Drunk $2
Action/Attack
+1 Card
+1 Action
Discard a card. Other players discard down to 4 cards
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Bone keeper $5
Action/Attack
Trash a card from your hand.
Reveal a card from your hand and gain a copy of it.
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Riches $4
Treasure
+$2
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When you play this, trash a card from your hand.
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Rummage $5
Action
Trash a card from your hand. Gain a card to your hand costing up to $3 more than the trashed card.
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Visitor from Abroad $5
Action
+1 Card
+1 Action
Discard a card. You may gain a card costing up to $5.
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Rummage $5
Action
+1 Card
+1 Action
Discard any number of cards. +$1 per card discarded. Draw until you have 5 cards in hand.
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I think the key to getting it to create anything interesting was have a long prompt that explained the game, and then gave lots of examples of cards that had significant text (i.e., not village and smithy). Even so about half of what was created was useful. The other half re-created existing cards or made no sense.
But not bad!
Ed