One particular design of card that I am taking an interest in is what I call, for lack of a better term, the "packrat" card. Basically, a "packrat" card is a card that lets the player collect cards from the other player, typically after they leave play. I would distinguish it from a "mind control" card that lets the player take control of another player's character (ex.: Stygian Eye), or a "thief" card that lets the player take control of another player's attachment (ex.: Thief for Hire), although they generally have the same effect: taking control of cards in some way.
Each of the packrat cards has a nominal advantage that they confer, but one major secondary advantage is in shutting down recursion, which is becoming a major factor in the metagame. The other player can't fish a card out of the discard pile if it's sitting in your Trophy Room. And unlike the mind control and thief cards, the packrats can hoard a potentially unlimited supply of cards, which is sure to annoy the other player.
While I don't think they are "include in every deck" powerful, I do think they're potentially useful under the right circumstances. The main difficulty, that I can see, is that they typically trigger when cards are removed from play - most often, when characters are destroyed. When you're behind in the game, just getting that trigger can be a difficulty. As such, they're not as good for turning around a bad situation as they are for staying in control. Even so, I like the idea of them and am interested in figuring out ways to work them into decks.
The "packrat" cards, as I count them, are:
- Specimen Bags (Syn, AtMoM) - potentially quite useful, especially for shutting down the "bouncing" metagame. Take out one Initiate of Huang Hun and attach it to it, and that's the last you'll see of them for a while.
- Trophy Room (Syn, MoE) - not as impressed with this one. Marginally easier to defend, as it's not attached to a character like Specimen Bags.
- Specimen Room (Shub, MoE) - as with Trophy Room, and mainly for Mi-go decks.
- Feasting Ghouls (Shub, TWB) - more expensive than the others, but the ability to actively select characters from the other discard pile is great, meaning you could potentially use the Ghouls to steadily mop up the other side's discard pile.
- Canopic Jar (Yog, TSS) - I really like this one, as it not only nicks the other side's characters, but lets you use their abilities as well.
- Fence (Syn, LR, just released) - I also really like this one; it not only nicks the other side's attachments before they leave play (meaning they can't go to the discard pile to trigger "after leaves play" effects), but they give the enterprising Fence the ability to use them right away, because, you know, they're attachments.
One rules question: Canopic Jar states that the character should be attached to it, but not as a blank attachment the way some of the others specify. Does that mean that passive effects on the attached character cards are in effect? For instance, if the Canopic Jar attaches the Jade Salesman, is the increased cost for attachments still in effect?
And one final comment: would be really nice to have a packrat card for events. Snitching the other side's events and keeping them bottled up could really wreak havoc on a number of the control decks that are currently very competitive.