Giant feedback post for every card I had thoughts on. Unfortunately, I only had a few pieces of meaningful feedback. Most of it is wording questions
Spectre
Night - Attack - Duration ($5)
At the start of your next turn, +2 Cards. Until then, when any other player buys a(n):
Action card: They take their -1 Card token.
Treasure card: They take their -1 Coin token.
Victory card: They gain a Curse.
Den of Sin does gain to hand (which is a HUGE part of the card), but on subsequent turns, this card is essentially Den of Sin+. Which doesn't feel right to me. I don't think Donald X. would design something like this when Den of Sin exists. I do like the interesting synergy of someone can just buy a Night Card to avoid getting attacked, and hey -- Spectre is a night card. But I think this is the kind of synergy Donald X. likes to avoid. When he designs attacks he likes to think about the balance of if everyone but one player buys the attack, is that too dominating? And in this case, it seems like it is because the player who does not buy this attack card will get hit by the attack more frequently than people who do. Think about a Witch/Moat fusion wouldn't be balanced in this way. You don't have to design cards the way Donald X. would, but if you want to, I'd suggest changing the next turn benefit to something like +1 Card +$1 +1Buy (I dunno, something besides +2 cards), and you could consider changing it to "Action card or Night Card: They take their -1 Card token."
Seance (Night-Gathering, $3)
For each card you gained this turn, choose one: trash a card from your hand and add a VP token to the Seance Supply pile, or take the VP tokens from the Seance Supply pile.
There's some strangeness here where the clause reads "for each card you gained this turn take the VP tokens from the Seance Supply pile" which leads to an ambiguity -- do you only take one token for each card you gained? You can avoid this ambiguity by rephrasing the clauses to make it more clear you take all the VP Tokens:
"Choose one: take the VP tokens from the Seance Supply pile, or for each card you gained this turn trash a card from your hand and add a VP token to the Seance Supply pile."
This is a cool card! I don't know if this is intentional, but Sarcophagus can self-exile when you play it. So it's sort of like buying a victory token. It takes space in your deck for one shuffle, then it exiles itself away to be worth 1vp. And if you get even one other card in exile (a silver for instance), then it becomes waaaay better than estate, far more than than the price merits. And better than many alt-vp for its cost. I think this is a little too strong Victory Point wise.
I'd recommend raising the cost to $4 -- it's a decent copper thinner already, better than many $3 trashers at thinning coppers and ruins (though it stumbles on curses/estates). You could also have it not be able to exile itself ("exile a non-Duration card you have in play besides this").
Warding Mask
$3 - Night - Duration - Fate
Take a boon. Receive it now or at the start of your next turn.
At the start of your next turn, you may put a card from your discard pile into your hand, then draw up to 6 cards in hand.
I didn't feel like doing an attack for this contest (My first idea was an attack, and I expect most entries will be attacks). The name is a reference to the old reason some people would wear masks on halloween: to ward off evil spirits.
What happens if you do not put a card from your discard pile into your hand, do you still draw up to 6 cards? I feel like there is some precedent to say "At the start of your next turn, you may put a card from your discard pile into your hand,
and either way draw up to 6 cards in hand."
Ouija Board - $2
Treasure - Night
+1 Coffers
+1 Buy
If it's your Night phase, remove 2 tokens from your Coffers to buy a Spirit from one of the Spirit piles. If the Spirit costs more than this, trash this.
A Ducat without the Copper Trashing, but allows the ability to buy Spirits at an upcharge of 2 Coffers (thinking of making it 3). I am unsure of the wording, but am going off the text from Butcher and Exorcist. Comes with a built in Buy so you can still buy something in your Buy phase if you want. Feedback is appreciated.
I think Buying from non-supply piles is confusing. And this card is confusing. Can you buy any spirit for 2 Coffers? Or do you mean that you pay 2 coffers and then pay the cost of the Spirit Pile?
Some possible wordings for both cases:
"remove 2 tokens from your Coffers to gain a Spirit from one of the Spirit piles. If the Spirit costs more than this, trash this."
"remove 2 tokens from your Coffers and spend any amount of $ to gain a Spirit the costs exactly equal to the $ you spent"
Also, should the removing tokens be mandatory?
This card seems to have more uses if you add "If it's your Night phase,
you may remove 2 tokens from your Coffers.
If you do..."
Also, I am unsure why this is a Treasure Night. The only difference is as a treasure you get a +buy, and as a night you can do that activity. But there is no inherent reason for the activity of gaining spirits to happen in the night phase and not the Treasure phase. This card could just be a Treasure. You're going to be spending two coffers to do the exchange, so it doesn't matter that turn if it was played as a Treasure or a Night.
My recommendation would be to explore the space to have it do something different in Treasure and Night that affects those faces. What if it gains a Coffer in your night phase, but gives $2 in your buy phase? That would be a more meaningful difference! Of course price would have to change.
from playing their Transfigure. Less than 
is better, but still has the problem of people not wanting to Locust themselves.
