You know, earlier I said I would spare posting every card from the custom set I'm working on, and would only post the tricky ones. Well, it seems like I'm posting cards from there in installments.
Rebirth
Cost: $7
Action
Choose 10 cards you own. Set those cards aside, trash the rest, and put all cards set aside this way in your discard pile.
Rulebook: Cards you own means cards in your deck, discard pile, hand, in play, or set aside by another effect (i.e. Island).
Random thoughts on it (once again, I haven't had the time to playtest it's effect thoroughly enough):
Cost is up in the air. Priced it at $7 because it's an odd effect, because you don't want it until later in the game, and because it compares to Forge reasonably well. It leads to interesting scenarios where you can buy the components of an engine that normally would be too slow, and then start it up in one shot. On the other hand, $7 is a really high cost to have that happen. You could choose to keep Rebirth in your new starting 10, but playing it effectively takes away your current turn, and it gets better when your deck is bigger, so repeated plays probably are not optimal. Well, unless you have enough money producing actions, and then it seems like Tactician silliness is better.
Each turn, you presumably buy 1 card (ignore +Buy for now). So for each turn that has passed, Rebirth has the potential to trash one more card from your deck. Which is actually not terrible, now that I think of it