I had been working on a fan expansion for a time. The expansion was based primarily on revealing cards from decks, which, beyond the difficulty of flavoring that intangible mechanic, got about as fiddly as you can imagine. The cards were largely complex and unwieldy and the few good ideas present weren't worth expanding into even a small set, let alone a larger one. However, some cards still live on as they divorced themselves from the admittedly weak mechanical theme. (By the by, I'm still working with the aforementioned set, but it is low priority).
This started as a card that wanted to transform into an Action from another player's deck. I played around with the idea for a while. I found digging through another player's deck was long-winded and took a lot of words to convey. Such an unreliable card needs to be cheap, but if it is effective, digging around in another player's deck slows the game down a lot. Looking at another player's hand was rather redundant because, not only could it miss entirely, but it would be played as a card that was likely going to be played just next turn which felt rather redundant. This all is, of course, assuming it is still optimal to buy other Action cards when another player can copy them with Orphans rather than simply playing a Big-Money deck.
Furthermore, I wanted it to have a consistent effect. I played with a couple of different effects (namely +2 Cards on one version, +2 Actions on another). A big problem with inconsistent cards like
Tribute is that it is sometimes nonterminal, but you won't know until you play it. The fact that this could transform into a
Village meant you would be left with a lot of bad feelings when you draw it "dead" with a
Smithy. On an inconsistent card, you can't really stand to be so unsure to whether it is terminal or not, so +2 Cards was out. +2 Actions seemed much more promising, but then it became the case that one would often buy Orphans to get the Actions and it transforming into powerful cards was happenstance. No good there either.
When
Band of Misfits came around, I took from its wording. Since then, I've tested it a bit and I ultimately have this:
Orphans
Types: Action
Cost: $3
If this is the first Orphans you've played this turn, shuffle the Orphans deck and then reveal a card from it. Choose one: +1 Action, +1 Buy, +$1; or play this as if it were the revealed from the Orphans deck this turn and this is that card until it leaves play.
Setup: In games using this, make an Orphans deck out the randomizer of each Action in the Supply costing up to $7 other than Orphans.
Orphans
Types: Action
Cost: $3
If this is the first Orphans you've played this turn, shuffle the Orphans deck and then reveal a card from it. Choose one: +1 Action, +1 Buy, +$1; or play this as if it were the revealed from the Orphans deck this turn and this is that card until it leaves play.
Setup: In games using this, make an Orphans deck out the randomizer of each Action in the Supply costing up to $6 other than Orphans.
Because it started using an extra deck, it really feels more like a promotional card than anything else, so I've started treating it as such. By the by, its FAQ would point out that it should be played as the top
Knight if the
Knights from Dark Ages are selected (and fails if the
Knight pile is empty). It is somewhat wordy, but it works.
The first time you play it you pick a random Action that each Orphans can transform into. Each Orphans you play can be a vanishing Copper with a Buy (bad enough that you don't want to load up on them, good enough that you won't despair when you draw it with a better terminal), but also might transform into something better.
Revealing a card from the Orphans deck is moderately troublesome, but gets the job done fairly quickly. Most importantly, the card is fun to use, even if you'd rather have something more consistent. In a lot of Kingdoms it is a very powerful card because there are a lot of $5 or $6 cards worth playing. In other Kingdoms, it's pretty terrible since it doesn't have any good targets. Trash-for-benefits are notoriously bad for Orphans.
The construction of the Orphans deck has changed since I first started testing it. Originally, it had every Action, but the chance of whiffing totally by drawing Orphans or striking big by drawing
Possession was too swingy, so I limited it to Actions costing up to $8 and removed the Orphans card from the Orphans deck. Now that has needed to change: I included $8 cards really just to catch
Peddler, but, as if hitting
King's Court wasn't funny enough from time to time, now you could hit
Prince? No thank you.
So, in case anyone wondered what transforming cards looked like in my head before Dark Ages, this was it.