Hello,
A few weeks ago, I came up with some cards that had synergy specifically with each other. But, they would have had the problem of being too weak when they didn't show up in the same kingdom. When ordered piles were revealed, it basically allowed the problem to be fixed. I'm new at making fan cards, so these are quite simple. So, Here are my cards:
Spelunker - Action - $1
+1 Action
Choose One: Look through your discard pile, reveal a Cavern from it, and put it into your hand; or +1 Card.
Ice Cavern - Action-Cavern - $2
+3 Cards
Discard 2 cards, trash a card from your hand, and put a card from your hand on top of your deck.
Sand Cave - Action-Attack-Cavern - $3
+1 Action
Each other player either gains a Copper per Cavern you have in play, or gains a Curse, their choice.
Moonglow Tunnel - Action-Cavern - $4
+$2
+1 Action per Cavern you have in play.
Hidden Grotto - Action-Cavern - $5
+1 Action
+1 Card per Cavern you have in play.
Canyon - Action-Cavern - $6
+1 Action
Reveal cards from your deck until you reveal 2 Caverns. Put the Caverns into your hand, and discard the other revealed cards.
Jungle Hollow - Action-Cavern - $7
+1 Card
+1 Action
If you have at least 2 Caverns in play, +1 Card, +1 Action, +2$
Miracle Tarn - Action - $8
+1 Action
Trash any number of cards from your hand. Gain a Gold per card you trashed, putting them on top of your deck.
They are mostly non-terminal to make it much easier to chain. Since they have had zero testing, they're probably really unbalanced. I would appreciate any feedback anyone has.