This has been an utterly insane summer for Magic. Three set releases in close proximity, followed by Hogaak, and then a major banlist update. Modern players are struggling to remember what it means to have a metagame, much less investigate one. We've barely had time to catch our breath for the past four months, and now it's time for another spoiler season.
Thrones of Eldraine spoilers have just begun, and this is a very promising set. Not that Modern actually needs new cards after Modern Horizons, but that also isn't quite what I mean. Eldraine is being billed as a watershed set for Magic. The setting is based on fairy tales, primarily Grimm ones, and that's something players have been requesting for years, which means lots of interesting cards that have likely been ruminating for a long time. It's also a set with the first Magic book in years, and more importantly several types of boosters. In addition to the normal packs we've been used to since the beginning of the game, there's also color-themed packs and a collector's version, which has alternate-art cards. This means many cards have been spoiled twice so far. Thus, I'm focusing on the mechanics of Elraine alphabetically, rather than on specific cards.
The first mechanic is Adamant, which is effectively scaled-down devotion. If you cast an adamant card with three mana of its color (i.e. a white adamant spell needs three white mana), you get an extra effect. At time of writing, there are no Modern-playable cards with adamant. However, should there be one, it will see a considerable amount of play.
Adamant is clearly meant to promote mono-colored decks in Standard, but the only reason that would happen in Modern is an aggressive white creature. Modern's mana makes it possible for Esper Control to run Cryptic Command alongside Damnation and Settle the Wreckage if so inclined. Therefore, a decent adamant spell could be run in any deck that wants it and is at least somewhat on-color. For example, a playable adamant blue instant could be run in anything from Merfolk to Grixis Control with very little burden, and the expectation that it will get the bonus almost every time. I expect that the front of such a spell can be a bit weak if the enhanced version is solidly playable.
It will take quite a bit for any non-white adamant creature to see play. The bar for creatures in Modern starts pretty high, and there are already a lot of creatures with heavy color requirements and considerable compensating power that don't see play. Phyrexian Obliterator is very dangerous to play against, but there's no deck that can actually harness its power. A similar mono-blue creature would be operating in Merfolk's space, while a red one would compete (probably unsuccessfully) for a slot in Burn. Death and Taxes-style decks have the flex slots to make such a creature work and could use some raw power for when their disruption isn't effective. We need to wait and see what shakes out.
The apparent centerpiece of the set, adventure is a unique hybrid of previous mechanics. A creature with adventure is a normal creature that has an instant or sorcery attached to it. If cast it as a creature, it just enters play that way. If players cast the instant or sorcery, upon resolving, the card is exiled. You can then cast the creature. This is a spell with a choice (modal), a creature that can play like a spell (evoke), and additional value from replaying the card (flashback). Spells with lots of utility and versatility are often Modern-playable even if their effects aren't the strongest in a vacuum (see also: Collected Brutality). The question is which side of the adventure spell is the attractive one.
The first casting mode is for the instant or sorcery to be the desirable effect. Here, the creature is a bonus that decks may not actually need. At time of writing, the only playable adventure cards are in this category. The effects are a bit weak on their own, but in the right deck or circumstance could be good enough. Getting a body out of the deal makes them more attractive than otherwise.
Animating Faerie: I don't know why any deck would want to make their noncreature artifacts into 4/4s. Tezzeret, Agent of Bolas makes 5/5s repeatably and sees no play. However, Ensoul Artifact has been run in Affinity before, and Bring to Life is arguably better. Yes, the creature is smaller and the effect costs more, but it also doesn't stop being a creature if the enchantment falls off. An Animated Darksteel Citadel doesn't fear Assassin's Trophy, where an Ensouled one does. And at the end of it all, you get a 2/2 flier to wear Cranial Plating. If artifact control gains ground or grinding becomes more important, I expect Faerie to start making it.
Embereth Shieldbreaker: Against any artifact heavy deck, Shattering Spree or Vandalblast will be much better than Battle Display for the same price. However, there will be plenty of times where such cards are overkill. If instead you want cheap, maindeckable hate, then Shieldbreaker is better than any other option I can think of in mono-red. There's also the benefit that against decks with only a couple artifacts (*cough* Stoneforge Mystic), Shieldbreaker isn't a dead card if they never play the artifact. A 2/1 for two isn't a great deal, but having the option to destroy a Batterskull first is.
Rosethorn Acolyte: Seasonal Ritual is Manamorphose's little sister, and Manamorphose is an absurd card in velocity decks. However, it's mostly been played in red combo decks, and mostly because it cantrips. Ritual has to be played in green decks and doesn't replace itself right away, but it is still a "free" spell, and fixes mana while upping the storm count; the velocity of Manamorphose is gone, but Ritual doesn't technically go down a card, since Acolyte can then be cast from exile. Acolyte isn't too far off Modern playable as-is thanks to being an elf, so I could see a some UG combo using Ritual to fix mana, then Acolyte to help ramp. The only current deck that fits the bill is Neoform, where Ritual would be extra fixing, with Acolyte available as the consolation prize for a failed combo attempt. If a Heartbeat of Spring combo ever emerges, Acolyte may fit right in.
The other possibility is for an adventure creature to be playable on its own, and the adventure part to provide the bonus. As of this moment, there aren't any examples in this category. Lovestruck Beast // Heart's Desire is close, but is too conditional; no deck wants to make a 1/1 Human token for G.
Even beyond that issue, what decks want a 5/5 for three with downside? Aggro decks like Humans may play 1/1's, but they don't stay that small for long. Ramp decks may use Sakura Tribe-Elder, but they don't even play Wayward Sawtooth, who actually supports their strategy. Beast is very close to playable, but I think there are too many question marks.
For a card to actually make it this way, I think it needs to be in the same vein as Reveillark. The front-end creature must be good enough to make a deck. The adventure part could be something fairly niche or situational that wouldn't normally be played, but in the right circumstance is needed. It remains to be seen if that will pan out.
The final formal mechanic is food. Food follows on from Innistrad's clue tokens and Ixalan's treasures as token artifacts created by reasonable spells as additional value. I'm unaware of treasure doing anything in Modern because there's no good repeatable way to make treasures. Clues do see play, mostly because of Tireless Tracker. Thus on face, it will take a generator at least as good as Tracker for food to be playable.
However, it will need to be quite a bit better, since food tokens seem much weaker than their predecessors. Clues are the strongest since they draw cards; treasure is as good as Lotus Petal. But food gains three life for two mana. That's not a great rate, and while a constant stream can potentially shut out Burn, they're not going to have much impact elsewhere. However, Wizards is apparently aware of this, and they don't really expect gaining three life to be the real utility of food.
Utilizing the Means of Production
Instead, Wizards appears to have designed food as a fuel source for other cards. So far, there are some decent ways to not only make food but also use it, which could mean that it makes the transition to Modern if the payoffs pay off.
Gilded Goose: The Goose lays the Golden Egg. Then, it pays tribute to Deathrite Shaman. Bring the kids for a fun day out! In seriousness, Goose is not in the same league as the banned-everywhere Shaman. That doesn't mean that it's not still playable.
By itself, Goose can only accelerate mana once, and requires food mana to keep it going. Goose is a weaker fixer than Birds of Paradise, but it also doesn't die to Gut Shot. If there's cheap, repeatable food generation, Goose could be a decent card. If there's repeatable flickering, then it becomes a good source of food.
Savvy Hunter-This is more what I'm looking for. Hunter's stats aren't that great, but repeatable card draw in BG is very good (again, see Tireless Tracker). Hunter's main limitation is that she only makes one food a turn, and so can only draw a card every other turn. On her own, she's not good enough. However, pair with another repeatable generation and there's an engine here. It's still worse than Tracker since it's not self-contained, but for Tracker to generate more cards a turn requires fetchlands, which also require life payments. In a Burn-heavy meta, that's not insignificant.
The other option is to feed food to a combo engine. Token artifacts are good fodder for any combo that wants to sacrifice artifacts for value. Krark-Clan Ironworks is the obvious engine, but it's banned and there aren't really good replacements. Grinding Station is the best pure combo payoff I could find, and it would take a very good token generator to be better than existing options. Urza, Lord High Artificer can make food into mana, though
The final mechanic, though not a formal one much like in Core 2020, is the palpable tribal synergy in Eldraine. The most prevalent one is for Knights. Apparently, there's a kingdom for each color, so there may be knights for each color, but so far all the Knight support has been Mardu-colored. This presents both opportunities and a problem for the tribe.
Modern is full of playable knights, and they're getting a two-mana lord in Inspiring Veteran. Given the additional fixing from Tournament Grounds, it won't be hard to put together a very solid aggressive knight deck. Many already have first strike and some form of protection or other defensive ability. Combine with the three-mana knight lords, and you produce a solid ground game of tough, mid-size creatures. Throw in Haakon, Stromgald Scourge and you've got a deck that will grind with the best.
That gameplan is very similar to Spirits, who have the benefit of flight. Knights also competes with Humans, which will necessarily be a faster deck with inbuilt disruption. And there's the problem of being a Mardu deck. Why be a tribal Mardu deck rather than Death's Shadow or midrange? It's going to take some very strong knights for them to finally make the cut in Modern.
The Fair Folk
The other revealed tribe is Faeries. Having fallen far since the days of Lorwyn Standard, Faeries is a deck that seems like it should be far better than it actually is given Bitterblossom and Mistbind Clique. Exactly why this is the case depends on who you ask, but I say it's a combination of the creatures being 1/1's, Burn existing, and the deck's difficulty to master. The power of the synergies is very good, but it takes so many to compete with other decks that it's barely worth trying.
Unfortunately for the holdouts, I'm not seeing anything that pushes Faeries back into contention. Yet anyway. The best cards are too expensive and/or symmetrical to make it in Modern, while the cheap ones don't gel with the Faerie strategy. Rankle, Master of Pranks looks very potent, but it's hard to make any ability but his first benefit you more than your opponent, and why bother when there's the cheaper Liliana of the Veil? I suspect that it will take another, beefier Spellstutter Sprite for Faeries to be good again, and I'm skeptical that such a card will be made given Faerie's history.
This is just the beginning of spoiler season. By next week, there will be far more individual cards to discuss and tales to tell. If nothing else, this is the most artistic set Wizards has ever done, and that's notable by itself.