not pointing this at anyone in particular but for the sake of not having to repeatedly mark down good cards in judging because of a simple criteria issue, I just wanted to highlight this part:

Hopefully there's room for designs where the reveal is technically necessary for some other part of the card, but it still feels like a meaningful drawback on its own.

I don't want to comment on any particular designs for the sake of fairness but, generally speaking, a card that did that would be fine.

Disinformation Exchange
Enchantment
Players play with their hands and the top card of their library revealed.
: Exile the top card of each player's library. Activate only once each turn.
: Each player discards a card. Activate only as a sorcery and only once each turn.

Villainous Monologue
Enchantment - Saga (R)
You can't cast spells. (Including plotted ones.)
I, II, III: Plot a nonland card from your hand or graveyard. You lose life equal to it's mana cost.

I've elected that Exile a card... it becomes plotted. is dumb phrasing. It should be like manifest.

starting grades!

Cruel Courtier
Creature — Human Noble Advisor
At the beginning of your upkeep, target opponent looks at the top card on your library and chooses a number. You may put that card in your hand and lose life equal to the chosen number. Otherwise, exile that card and that opponent loses life equal to the chosen number.
For all its evils, war is a game that you at least know you are playing. No such nicety exists for politics.
1/1

I think this card already exists, but I am shooting this off before I leave the house.

Bumbling Spylet

Creature - Human Rogue
Bumbling Spylet can't be blocked.
Whenever Bumbling Spylet deals combat damage to an opponent, reveal your hand to that opponent.
Getting in and out isn't his issue, it's not leaving behind a trail of evidence that he hasn't quite mastered yet.
2/2

cute. I like how, despite the flavor text, the effect is ponder, not preordain. limiting your opponent's options here makes it feel a bit less punishing while still giving them significant control. I also agree with you on balance: it's still overall a pretty clear upside, but the drawback should give you clearance for the +1 power over elvish visionary. is this really giving information as its primary drawback? feels close enough.
4/5

really good. as you say, very technically this does require the reveal in case your hand is all lands, but I don't really care about that. should maybe cost since it's mainly a sidegrade on coercion, but coercion isn't really the standard anymore. still, might as well be nice to multiplayer tables. anyway, that aside the flavor's great, the card's interesting, and it fits the criteria really nicely.
5/5

this feels like a thing I'm gonna say a couple times this round, but messing around with player control feels like swatting flies with a nuke. you could just as easily get this effect by spelling out the options they have ("Target opponent looks at the top 3 cards of your library, then puts any number of them on the bottom of your library in any order and the rest on top in any order.") or just use fateseal, and then you don't have to untangle all the dangerous implications of temporarily granting an opponent control. the card seems solid otherwise, though, and the flavor's nice. there is some question of whether the main thing it's giving away is information, as opposed to control, but I let Cato get away with it.
3/5

I like this but I think I'd prefer if it changed at end step instead. the most useful thing to know is, on my turn, what are you doing on your next turn? and this doesn't give me that. it forces me to show you any responses I plan to do, but if my deck is more proactive, which I'd expect from a 4-drop serra angel, that's unlikely to be a huge problem. swapping on end step means committing to my next-turn plan, so you can make choices that take advantage of that information more effectively. still, cute, and good flavor.
4/5

similar thing to Tevish but more significant because they'll control you while you while you have priority, leading to lots of possible choices that have nothing to do with what the card's trying to do. I think that's maybe intentional here, since a 3/3 for 1 is a lot so the drawback should be big, but it still feels pretty orthogonal to the overall point, and pulls pretty far away from the question of information as a primary resource being spent. flavor's also weird in that context: how is this guy so angry that the prodigal pyromancer sitting next to it doesn't get to choose who to target anymore? feels like if you are gonna go in the full control direction, it'd take a lot more justifying.
2/5

I like the idea, and the flavor's good. I'm not sure you need the spending restriction, though: colorless mana is already a significant drawback. I get that the point is so you can't just go hellbent to remove the drawback of the reveal, but that's its own drawback anyway and I think you could save the awkward wording. speaking of which I wish there was a better way to do the if-this-was-tapped thing but I don't know what it is. overall though it's a fun idea, forcing you to warn your opponents of what you're gonna use the mana for, and once you've done it once, you can even try to bluff an answer by not revealing again when most of your hand is known to imply you don't want them to see the hidden card.
4/5

is this enough to justify such a huge body for a 2-drop? maybe, but probably not. not sure what the revealing part has to do with anything. I guess it gives them a little extra info to start in conjunction with the other ability, since they'll know which, say, 3-drops you have available. still, though, not sure I get it. but I do like the restriction. kinda like Shrimp's but with a bit less information given away. still enough to seriously restrict you if you choose wrong, though, and especially in tournament play where your opponent is likely to know the common cards in your deck, they can do a lot of planning around being told that number.
3/5

I'm torn 'cause I like the idea of this but, by default, I'm looking for cards that can exist in paper sets, and this is clearly digital-only. I mean, there's nothing in the rules that says this doesn't work in physical play, but it's got no room for cheating prevention and no easy way to fix that without requiring you to reveal your entire deck to your opponent, either when you cast it or at the end of the game. and it's such a shame 'cause it's a really lovely design for a digital set. I just don't feel like I can grade it fairly against other entrants, y'know? but I do like it.
3/5

I'm generally torn on whether Companion is primarily about giving away information, but in this case knowing you have no action on their turn is a huge advantage so while I'm not sure, say, jegantha, the wellspring really counts, this certainly does. (technically you could still have action with, say, channel, but that's an edge case and you can easily keep this out of standard with those.) I do wish the abilities were different, though, especially since they pull in opposite directions. I'm not sure exactly what I want them to be but I just don't find this version inspiring in the way the initial companion promises. it's a great take on the challenge, though, and I love the name.
[c]4/5[/b]

I'm always ambivalent about the [c]goblin spy[/c] ability because of how much it kills the flow of information, but I think this makes a strong case for itself. the numbers are aggressive enough to actually want the body on its own merits (as opposed to spy) and by being an early aggressive threat, it encourages your opponent to kill it and lose access to that info. very similar vein to the prompt card, but different enough in enough ways to carve out its own purpose, and the flavor's a good extension of its mechanical implications.
5/5

I liked the earlier, less complicated version of this better. it still works, but I liked how it sort of inevitably ticked downward. this is just Maro with a fiddly hand-reveal clause, but it's hard to imagine not wanting to exile any given thing I draw. maybe I can get some bluff value out of making the choice to shrink my threat in order to keep a card hidden, but I'm probably not running this with many cards I want to hide. does add the graceful adept ability to it, which is nice, but the wording gets really messy since you have to repeat the "you may play those cards" thing twice to avoid the version where you lose them if your Mistmaro dies. I dunno. just feels messy now that the exiled cards are literally just a replacement hand.
2/5

I don't mind cards that are more interesting in multiplayer, but I'm generally not a huge fan of cards that are only interesting in multiplayer. I'm also not sure what the looking at each other's hands accomplishes? beyond fitting it to the criteria. it's maybe helping with the flavor of an exercise if you know each other's plans, but mechanically it has basically no impact on the rest of the card which is a shame 'cause it's the only part of this that fits the criteria. I like the damage dealing clause but I think there are better ways to use it.
1/5

feels like a stretch to call the existence of a duration a drawback. is the fact that you can still die on later turns a drawback of angel's grace? if anything turning them face-up for free is an upside: you can use it to skirt expensive morph costs, or to sneak through valuable saboteur abilities. that moment where they get flipped up is exactly when you'd want the cloak to expire. I do like the card, it seems like it'd be fun to play with, but this feels like the opposite of giving away information.
2/5

suspend as information-giving makes sense. I wonder if doing it from library is the best way to capture that, though, since it's giving information that otherwise wouldn't exist. still, giving them forewarning of your plan. I'm surprised this doesn't exist yet, it's very straightforward but in an effective sort of way.
4/5

ok, I'm kinda lost here. reckless as a keyword seems plausible in the vein of defender, but beyond that I don't really get it. the scale of card accumulation is slow enough that the drawback doesn't really go anywhere, madness for a whale is a flavor fit for the source material but really specific mechanically (there are 15 whales in all of Magic) and not tied in with the rest of the card, and it's also not even like you're giving your opponent usable information: they can look at the cards, but what can they do with knowing cards you're not gonna have access to? I'm struggling to tie this together into a coherent card, or into something that meets the criteria.
1/5

courser of cruphix without a body? sure, seems plausible. they'll probably print it at some point, although I doubt it'll be with such a restrictive cost. still, that ability has never really treated the reveal as much of a drawback, so I think it falls into that thing I was saying in the OP about cards where the revealed information is incidental to the design. when you're considering running courser of cruphix, or conspicuous snoop, or future sight, you're not really trading the revealed information against the strength of the card overall, you're just looking for the effect in general and that reveal happens to be part of how that mechanic works, like how tutors with conditions have to reveal to avoid cheating. flavor's nice, and the design makes sense (although I think it's weaker than courser, so seems likely) but it's not super exciting and it doesn't really do what I was looking for this round.
2/5

the connection here feels a little tenuous. it feels like the activated ability should involve some input from your opponent to take advantage of the information imbalance, but here all they can really do is prepare, and maybe bluff that the card is stronger to get you to pay the life. I do like how, if they do that and you activate it, you're stuck with it even if you can't or don't want to play the card: it doesn't just exile and let you cast from there, it leaves it on top so you have to use it or draw it. and viewing the second ability as a pure drawback that's not meant to be tied to the third, it is definitely interesting if maybe a little physically fiddly in in-person games. vigilance on a 2/2 for 4 seems kind of unnecessary but whatever, evergreen keywords are low-load.
4/5

similar to Parad's, the drawback here doesn't really seem to be the reveal itself, it's more in the vein of, like, skill borrower where the reveal is just a necessary precondition of the actual effect, but at least here that effect is itself kind of a drawback. honestly feels pretty similar to ELC's card in that way, although I like that one better here because it's more consistent and the reveal is a straight drawback. although this does also give away some deckbuilding info in that you're not running it with things that cost 4 or more. still, though.
3/5

lantern control in one card? seems dangerous, especially since it jumpstarts your information by revealing hands as well. I do like it but I think, given how annoying it could be in practice, it'd make more sense to put it on a creature so you could cost it up to fit a larger body. still, that's probably the only thing I'd change: make it, say, a 3/3 for and I think it's a contender.
3/5

so the info here is the set of spells you're gonna cast at the end of it? I guess Plot is, itself, kind of about info-giving as a drawback. I mean, it's mostly about tempo, but the reveal is there too. doesn't really read as info though. the card is interesting, feels pretty weak in most cases but is probably one of those ad nauseam designs where it has to look really weak in order to be even remotely balanced in the more degenerate situations it's actually built for. still, very slow. which is fine, just observing. I think it's a solid design, just not entirely sold on it for the round.
3/5

it's interesting in that the information disparity only exists for a second, but it still feels integral to the mechanic's design. is the mechanic a drawback? I don't know, but I really like it. the game seems really interesting to play, and if your opponent is worried about their life total they can always just opt out by picking zero. (or 1, more likely, to get at least a little damage.) I wonder if this wants to be an 0/1, but in practice there's not much difference between the bodies. just might be more aesthetic if it didn't actually attack for damage. still, lovely card.
5/5

ha, very cute. kinda similar to the prompt card but the flavor's very different and I like the execution. could probably be cheaper: phantom warrior is old and this isn't even better than that without the drawback. more recently there's jhessian infiltrator and even mercurial spelldancer which make this feel pretty underwhelming. doesn't have to be quite as pushed as spelldancer, but seems like a bare minimum to make this considerable in limited. other than that I like it.
4/5

a lot of folks took the criteria more loosely than I intended it to be read, and given the frequency of that I'm going to have to concede that it's probably my fault, not y'all's. could've written it clearer, sorry about that. tried to be reasonably generous in my interpretations where possible to compensate. anyway I think for me the clear winner here is Jim! congrats, nominating now.

Thanks! Regarding the power level note, though, we get Coercion at two mana now. See Pilfer and Binding Negotiation.

Actually, I didn't see this while designing, but Thought Erasure is a good comparison. My card exchanges surveil for looting at the cost of revealing information. That does put it on the pushed side for sure, but I could see it being printed.

Anyway, I'm glad people like the design! I was especially happy with the clean multiplayer buff, since these effects are always bad there.

I figured control during the scry was less nuclear than it might seem -- at most, since it is during resolving an effect, it bleeds more relevant information: your hand and the identity of any facedowns, rather than letting them activate mana abilities and do other screwage. It might have been better to go with the wordy option that doesn't use player control though.

The clause accomplishes players knowing there aren't any dirty tricks on both sides and sharing information for allying.

It's mostly mechanical flavor tho. IDK how everyone else came up with perfect cards this week, this criteria is impossible.

Personally I'm just not that convinced revealing information by itself is all that interesting or mechanically relevant, so it's hard to make it a central part of the design. I think the only existing card that does it in a cool way is Medomai's Prophecy, which was the starting point for my design before several iterations, and that card technically doesn't even fit the criteria since you can just name something you don't intend to cast. Sure, Sphinx Cub is a cute design, but it's not that compelling to actually play with, and after it and Goblin Spy you have pretty much exhausted all of that design space.

not that I'm complaining about your criteria or anything

I decided early on that information should extend to "anything you could plan to do as a player." This still leads mostly to revealing, but I felt that "must attack" fit within the parameters.

I wanted to rework the static abilities but was way to busy this week. I'm glad the bug still did well.

My card is misunderstood genius! No, I'm kidding. I was completely at a loss at how to create a card for this criteria and so made the first thing that came to my head and then just started layering things in.

changing at your end step somehow feels redundant to me, in the sense that if you play one or more cards during your turn you can already finish up by selecting a card that you'd want to save for your opponent's turn. having said that, it certainly makes the drawback a lot more meaningful, so it's probably a better way to achieve what the card is trying to do

yeah I don't think in your case it's all that dangerous, since there's no space to pay costs (or even activate mana abilities), I just feel like player control is a ten-foot-pole situation and needs some really strong justification to make it work.

yeah that's fair. not my favorite criteria or anything. like you say the card's cute but its appeal is so clearly tied to its specific bundle of things that building a broader challenge around it was difficult. could've gone in a flavor direction but it felt like the card probably won on its mechanics and I try to follow that wherever possible.

that makes sense. my feeling was that there's a difference between giving information and creating restrictions: a clearer analogue, then, might be that you have to communicate in advance whether the creature's gonna attack, although I don't know how fun a design that would actually be in practice.