Agistor by FragasnapThis is more like Research than Apprentice, and I treated it accordingly. The major advantage over Research is that Agistor does not dud if you have already drawn your deck. You also get the interesting self synergy of trashing a Horse to Agistor and netting two Horses. Animal Fair plays very well with it, offering a compelling benefit no matter which trashes the other. In fact, you will probably do both during the game.
Angel by anordinarymanA very interesting design space but also a highly centralizing specific card. The most important effect that I noticed is that many $3 cards are not appealing anymore after opening Angel/Angel/Angel, so I would usually find myself gaining Silver. I think the strength of the trashing needs to be cut back. Please explore this card type more.
Animate by GrepThis one gets wild with self-trashing cards, promoting Pixie or Raze rushes, which, incidentally, is a good reason that it doesn't hand out Imps. The smaller number of Ghosts compared to typical piles makes a good limiting factor. Still, it can't go completely off the rails because you have to buy other actions so that you don't end up in a Village Idiot type situation where your Ghosts have no good targets.
Attendant by MarpharosThe on-trash effect is very useful to complement other trashers, but the on play is too inconsistent and minor to justify putting in the deck. If you can regularly trigger two of the effects, you are probably choking on victory or curse cards.
Charity by spinefluThis is another $5 Gold with drawback like Cache or Contraband, but the drawback here is especially painful. You might spike to a useful price point, but you are also making it much easier for your opponent to do the same. It does not seem worth it. Other cards in the same design space (Governor, Council Room) have much greater disparities between the benefit to your and to your opponent. On top of that, $4<4> is a very high price to get the card into your deck while not playing nice with TfB cards, and buying it specifically to gain the Wish later seems like a wasted opportunity to buy the card you want now.
Curator by AquilaI apologize, I never got around to testing this one. It like that the money it can generate gets high for its cost but is necessarily limited by the turn count. The synergy with draw-to-x is also very nice. Keeping track of the cost in irl games seems like a chore, and the "set it aside" clause is overkill. The gain is already rather strong.
Dandelion Field by Xen3kSimilar pile-out math to Rubber Duchy below. The noteworthy differences are that it is not an eternal junk card in your deck and thus safer to buy earlier and that the payoff conditions may be met over multiple turns. Appeals to the Distant Lands enthusiast who wants to get away with not spending actions.
Glade (Lost Book) by RhodosThis pair offers very strong trashing once and weaker trashing otherwise. It doesn't lend itself to over-trashing and is much better on the 3/4 split than other Woodcutter variants because of getting an Estate out of your deck, though then you have to calculate when it is worth it to have two Woodcutters in your deck in order to get rid of 4 Coppers--too early and you risk terminal collision. Glade plays well with TfB cards by getting rid of the cards that are poor targets while supplying a nice $4 if necessary, especially if you want to risk buying that extra Glade specifically to trash one more junk card.
Grindstone (Scraps) by alion8meGrindstone is certainly too powerful. Five cards for $5 is more than the more expensive Hunting Grounds even if it does have a drawback. On the other hand, Scraps is very fun. It makes for a nice Ruins-like card with a hidden advantage. I would like to see other cards that make use of it, though it needs a different name after Menagerie in order to prevent confusion.
Insurance by majiponiThis one sees its best work in kingdoms with trashing attacks or self-trashing cards and a little less good with Remodel Variants. It can pick up Golds that were Remodeled into Provinces, but, by the point in the game when that is happening, you may not have time to take advantage of it. Being cavalier about trashing engine pieces will be more safe with this.
Junkyard by mail-miJunkyard is like a Shepherd that provides its own fuel. It has the potential to choke your deck, but this is reduced by pairing it with other sources of draw. The calculus surrounding megaturns is very interesting: not only do you have to weigh trashing the Junkyard for that small bit of extra draw, but you may have already emptied the Ruins by that point in the game, making every Junkyard harder to activate. Be careful that you have not helped your opponent three-pile you.
Marshland by faustMarshland plays very differently in different kingdoms. Ample gainers and you have a Gardens rush. No buys or gains and you have a sort of overpay chicken. There are bizarre interactions with Rogue and Graverobber since you can actually make the value go down instead of up. Is it really a benefit to trash my copy when my opponent is holding his? I would have to play this many more times before I really understand it.
Reconstruct by silverspawnThis card reminds me of a cross between Feast and Treasure Map. The set up is hard, and the pay off is not very interesting. Managing to play two in one turn and trash a third on the second play is enough for a Province, but that is three buys, good village support, and plenty of draw/sifting to get it to happen. It is a better card in games with Desperation or Pooka as a way to lessen the blow of cursing yourself (also giving Pooka more to churn) or if there are especially good $2 cards for burning your estates.
Refinery by Jonatan DjurachkovitchThis card also plays differently in different kingdoms. It reminds me of the bimodal Nocturne cards like Tragic Hero that could work for different strategies but have to be manipulated carefully to make it happen. It plays especially well with other gainers.
Rubber Duchy by LibraryAdventurerA very amusing card. It has certain qualities in common with Feodum: a TfB target that leaves behind more targets. The major difference in that respect is that Feodum gives you payload after you crack it, whereas Rubber Duchy is the payload itself, but only if you can trash it twice in one turn. The set-up rules also make Duchy-dancing less effective but simultaneously easier if you have the buys or gains. I did not play enough games to tell, but I expect pile outs are a big deal.
Silver Ore by lompeluitenSilver Ore spikes really hard due to the coffers. It might be par without trashing, but with trashing, the extra coffers get you into a runaway loop. Spices is already pretty strong, and Spices BM relies on the coffers to run smoothly. Silver Ore, at $3, is a lot easier to get a larger pile of coffers out of (even if you are missing out on the buys). I feel like it ought to cost more or cost less with reduced effect.
Snake Oil/Charlatan by D782802859Snake Oil makes an interesting comparison with Mill. Effectively having fewer Estates and more Coppers in your deck improves the average cost of cards you are buying early, though it is less impressive than Mill for that purpose unless you have support like cheap extra buys. The on-trash effect is very nice for giving one last boost at the point when it has outlived its usefulness.
Charlatan, on the other hand, is overtly powerful. If it was its own pile, it would be wildly overpowered. In one of my games, I used it to gain or buy a total of 5 Provinces and a Duchy in one turn. That is definitely a split you can not afford to lose. I would still price it higher because playing three actions total with the option to play treasures instead is all the best parts of Crown and Procession simultaneously.
Strategic Village by NoMoreFunI played a game with this and Bishop which went sideways. My opponents took advantage of my Bishop plays to get their own Hirelings on the board. One did not even get his own trashers. Speaking of Hireling, I think this is overpowered at $4. It is far to easy to get that permanent +1 card. The consideration of needing the bonus action could give pause on the decision to trash but not when other villages are present. I find the balance on that decision very lopsided.
Valkyrie by gambit05It looks balanced on its own, but it spirals out of hand with the right trasher or exiler. Catapult, for example, is not especially fast, but it does easily get 6 different cards into the trash by itself. Valkyrie handles the exiling side and then gets trashed at the right time for a giant pile of tokens (plus a Curse to your opponent for good measure). I am not sure how to balance it because it seems either grindingly slow or bananas with no middle ground.
Wand by mandioca15If you trash the card by the end of the game, there is no drawback, and you don't even lose buying power for doing so. Far too powerful.
Way of the Tardigrade by grrgrrgrrAbsolutely bonkers. Village+Death Cart is $10 without much effort. Hermit makes an entire functional deck out of cards that cost 3 or less. Urchin draws your entire deck. The concept is a lot of fun, but it requires some sort of limiting factor, perhaps setting aside the card to be discarded at clean-up.
Winner: Marshland by faust (7-3i points out of 10, would get confused again)
Runners-up: Junkyard by mail-mi, Dandelion Field by Zen3k and Rubber Duchy by LibraryAdventurer