Okay, time to judge. The submissions will be in no particular order. I'm sorry if I'm harsh against your card, don't take it personally.
Doppelgänger by alion8meThis is a really interesting card, and it is a bit similar to a Wish. It is a bit hard to evaluate the power level of because of the weird cost. In some kingdoms it could be an automatic buy, but the cost and effect have a nice balancing interaction. Sometimes can be worth it to try to pick it up fast, with an all or nothing opening of moat/moat or something similar. I don't like that you could buy this and a $5 on a moderately good turn if you are lucky enough to do so, maybe you could add a low $ cost, to make that harder to do on accident?
Voyager by D782802859Can be useful to have a few of these to thin your deck throughout the game, but doesn't solve the Freeze mechanic problem of leaving a mess of cards and tokens all over your table.
Celebration by SilverspawnThis one is probably pretty akward to play, what's with all this drawing in your buy phase? Feels like a sad Inventor, but isn't that useful except for megaturns.
Glade by AquilaInteresting, doesn’t seem broken, and two horses is an okay incentive to buy this early. I feel like you would want to buy this around turn 9 or 10 for most benefit, when you would typically want to green. Interesting concept, since there is not much incentive in Dominion to green early. I think I would prefer this if it only gave you one Curse instead of two, so it's better than estate points-wise.
War-torn Village by Xen3KThis is probably about as strong as Hideout in Spring or Summer. I like the late gaining of Mercenaries, but it doesn't at all fit with a Village, since you want to keep your Villages to support your terminals, and with this card you will probably not have any fodder for your Mercenaries by the time you can get them. That's why the Mercenary option is a big risk, and probably not worth it.
Privateer by LibraryAdventurerThis is broken. Giving your opponents Mutineers is a bit like gaining a VP token, and since this one doesn't have any restriction, you can just keep playing 6 of these a round, gaining a Province's worth of point lead every turn. It has all the problems cantrip +VP would have, and can lead to unfun, drawn-out games and stalemates.
Machinist by NoMoreFunThis is probably really strong, playing a $4 twice is a strong one-shot effect, but this one leaves you with a workshop and the played card afterwards.
Sanctum by SpinefluThis is probably a good version of the Wonder mechanic, but the actual effects are no good. In a no-trashing game, letting one player Donate once would be extremely swingy, the one who makes most steps wins the game. This is worsened even more if the Build card is a $5, and one player gets it in the opening and the other one doesn't get it until turn 5, and doesn't have any chance of getting it.
Sumisu by gambit05I like the idea of a draw card gradually getting better, but the wording is weird, and the interaction with other 痛 token cards is a bit unclear. If you have both this and silverspawn's Tera, does everyone start with 10 痛 tokens? That would make both cards much worse. Also, this has no reason to use specifically 痛 tokens, and could be any type of token, or have something similar to Pirate Ship.
Upheaval by spheremonkThis feels suspiciously similar to Imperialism by Asper, and doesn't add that much to the game. "Aha, this game we use Platinum but not Colony!".
WinnerDoppelgänger by alion8meUses the card costs in an interesting way, has an interesting duality. Although I don't think that this is the best version of the card, it is probably balanced.
Runner upGlade by Aquila
, not the other way around.