I'm back! I will insert cards that were added since my last round of comments.
Blind Bet - this says "random card", but that needs to be further specified I feel like. What if they previously revealed their hand or you played a Blind Bet before, are they then allowed/required to shuffle their hand? Other than that - this probably needs Command type and restrict to non-Command cards for playing in order to prevent infinite loops. I also feel like getting Woodcutter as the fallback option is a bit too strong; maybe cut the +1 Buy, otherwise frequently enough you'll play this as just a Woodcutter and ignore all the fancy stuff.
Clown - like a cheap Jester, but with opponents choosing? It not a bad concept, but the unconditional discard from hand can lead to nasty pins in Victory-heavy games (Shepherd?). The worst thing is that when I get an all-Victory hand, not only is it dead but I might also be forced to eventually discard a Province, which is just awful. It also has a bit of a political edge to it. I don't think I would enjoy playing this version, especially in multiplayer.
Faithful Knight - I feel like this had a previous, simpler version that I quite liked. [Side note: it might be a good idea to keep a changelog of your cards available somewhere - I noticed that you changed some things snce the last time I checked this out, and it's hard to follow discussion if this happens unannounced.] Ah i see it now, it exchanged for other tokens. You removed that option saying that you'd always immediately spend these tokens; I disagree. Especially if there are other sources of VP, you might just have a single Faithful Knight and want to hoard up. The current version of this is quite weak in comparison. The "more than 10" condition is awkward and unnecessary; it's a terminal VP gainer like Monument, and Monument doesn't cause any "neverending game" issues in practice.
Fairy - I like it. It might cause piles to run too fast, to the point where using this to Duchy-rush is viable; that would need to be checked in playtesting.
Four Seasons - Theme is never super strong in Dominion I suppose, but it still irritates me that you can "own" a Season. It's unclear to me how many Seasons there are; that seems very important. This is a specialised gainer that you will keep around, so in order to make it viable there need to be a decent amount of Seasons. It also allows for weird strategies where you "block off" one Season in order to prevent your opponent's exchanges; their viability also depends on this. The seasons themselves could be a bit more thematically match I feel like: fall should be the $ generator (because Harvest), and then +actions also feel more appropriate in Summer. Winter for buys and Spring for cards is reasonable.
Overall, this is probably a decent set, but it will be tough to find the balance in numbers that makes them neither overpowered nor too niche.
Ghost Pirate - I assume that the choice is the opponent's. I am saddened that this does not fall in line with preexisting flavor - Pirates/Thieves to steal treasure and Ghostly things to topdeck stuff. I think power-level wise, this is fine, and the attack takes a bit of setup to really hit hard, so that is also nice.
Gladiatrix - I have a lot to say about flavor these days. I don't think it's great to use female versions of existing cards, it's confusing and kind of rubs me the wrong way. In general I don't feel that card names should be gendered. I like the gambling aspect of this; in a way it is like a super-Tournament that is easier to blcok. And of course in the opening is's basically Priest. It#s pretty strong, but it can be awful if your opponent blocks you in the late game.
Gravedigger - This card does a bit too much for me. It's hard to wrap your head around. i think it can get rid of the Copper trashing benefit, that is not its main focus and it's pretty slow when used that way anyways. That should also allow you to put normal-sized text on it. I am not sure how well the trash-gaining works, it seems like you need to trash ever more expensive cards in order to reclaim what you trashed before, that's not viable. I feel like most of the time, the trash-gaining won't be relevant and this will basically be a Salvager variant. Which is fine, but then you maybe don't need that part either.
Guildmaster - I thought this was a cool concept when I saw it first in the design contest. It's good that this will always be terminal, because Young Saboteur spamming could get pretty annoying. All the options feel mostly balanced.
Heiress - again, it feels like this could simply be called "Heir". I don't understand the on-play effect; this does not seem to give any +Actions to begin with? I am not sure that "being played by another Action" is a well defined concept anyways; it I play Black Market for a Scepter that plays Heiress, was Heiress then "played by another Action"? I think this is certainly way too good at running piles, it can just empty its own pile and then probably one more on a single play. Maybe the on-play was meant to limit that?