Four sets rotating out of Standard combined with a new set entering the format is a massive shakeup. Generally in these situations, we see very few decks survive rotation.
Decks are more than just a product of how many good cards they gain or lose. The best decks in Standard are almost always decks with powerful cards that also contain strong synergies between the cards themselves. Even if new replacements spring up in a new set, that loss of synergy can sometimes be backbreaking for a strategy. Alternatively, a new format can look way different than the old format, and some decks are simply products of their environment and won't thrive in a new one.
With that being said, I think things might be a bit different this time around. Mainly, I think both Ixalan sets and M19 are the three weakest sets in Standard. Most decks in Standard are based around the sheer power of the three Ravnica sets, which aren't leaving the format. M20 was also an extremely impactful core set. The eighth set in eight-set Standard rarely has an impact on the format, but M20 actually created lots of new powerhouse decks.
I believe a lot of existing decks will continue to be strong in Throne of Eldraine Standard. Here are the top five surviving strategies.
This deck ultimately does not lose too much. Merfolk Trickster isn't even an integral part of the deck and is totally replaceable. One of the biggest hits is actually Hinterland Harbor's rotation. Without Harbor it's a lot harder to have good mana to cast Nightpack Ambusher or Frilled Mystic on curve. Either you're playing lands that enter tapped or additional basic lands, making it tougher to find the UU and GG you need to effectively play your spells.
Spell Pierce also hurts to lose. Spell Pierce was an integral part of blue tempo decks in the last format, and there's really no easy replacement.
With that said, there are a ton of upgrades for this deck in Throne of Eldraine. Brazen Borrower is basically the perfect card for this deck. Disperse is already a playable effect in this strategy, and Brazen Borrower offers instant-speed bounce, or a 3/1 flash flying creature, or both. Each side of this card does exactly what you want, and you can even do both!
Once Upon a Time offers potentially free, but definitely instant-speed fixing. This card can help fill the void of a missing Hinterland Harbor by offering lands when you need them and creatures when you don't. Castle Vantress and Fabled Passage also offer potential manabase upgrades. They aren't as clean as the untapped dual land that Hinterland Harbor offered, but they're still decent.
Wildborn Preserver is a strong replacement for Merfolk Trickster. I'd argue that it's even better. For one, it's easier to cast, and secondly it offers yet another flash two-drop that has the potential to grow as the game develops. Paired with Brineborn Cutthroat, the creature base is certainly not the weak part of this strategy.
Other considerable options are Oko, Thief of Crowns and Mystical Dispute. While Oko does not fit the flash theme, it might just be too powerful of a card to not play. Mystical Dispute is probably too weak to maindeck, but offers immense value as a anti-blue sideboard card. One mana for Mana Leak is too good to pass up.
Ultimately, I think this deck is going to be a little short of tier 1. While the flash creature base is going to be insanely good, I think it's a little short on the spells to enable it. I believe it will still be a decent deck, though, and if the MTG Arena ladders have anything to say, it's going to be a very popular deck. People seem to love this style of play. It's not for me personally, but I don't begrudge anyone for slinging some Frilled Mistakes.
I've had goosebumps for months just thinking about the raw unbridled power of Esper Hero after rotation. Unfortunately, something I was banking on did not come true, and it has soiled my dreams among other things.
I was banking on the remaining Temple lands being in Throne of Eldraine. That is not the case. That puts us in an awkward position where we are either stuck playing some dismal dual lands that enter play tapped and gain a life, or an excessive amount of basic lands. The former slows us down a lot, and the latter significantly reduces the consistency of the deck.
Another knock against Esper Hero is that the strength of the deck is in Hero of Precinct One, which thrives off of multicolor cards. M20 added nearly nothing to the strategy. It wasn't a multicolor set, after all. Throne of Eldraine likewise offers very little to the deck.
Sure, there are cards like Murderous Rider // Swift End that could make the strategy off sheer power alone, and the new lands like Castle Locthwain seem really great, but none of these cards offer significant power level boosts to the deck or fill the void left by Teferi, Hero of Dominaria.
So while Teferi, Hero of Dominaria and the check lands are really the only cards that Esper Hero loses, it still hurts significantly. Teferi was the best card in the deck and irreplaceable. However, even short a Teferi, I still believed that Esper Hero would be a great deck after rotation, perhaps even "The Deck" of the format. Now, without help to the mana base and without any meaningful upgrades from Throne, I'm reduced to believing it will merely be "A Deck."
The two big losses here are Reckless Rage and Adanto Vanguard. Basically the entire rest of the strategy remains, which makes a lot of sense when you consider that nearly the entire deck is comprised of War of the Spark cards.
Adanto Vanguard isn't too bad of a loss. Yes, it is a strong two-drop creature, but there are plenty of other playable options. Reckless Rage is a huge loss, on the other hand. The reusable removal spell when paired with Dreadhorde Arcanist or Feather, the Redeemed or both was a fairly integral part of the ability of this deck to grind out other decks. There is really no replacement for Reckless Rage and the deck will suffer some as a result.
Much like Esper Hero, there aren't a lot of great upgrades to this deck from Throne of Eldraine. Creatures like Robber of the Rich could slot into the Adanto Vanguard slot, and I think Outlaws' Merriment is an incredibly powerful card—reminiscent of Assemble the Legion—that could easily just be worth playing in every single white-red deck on raw power alone.
Outside of that, there isn't much. Some white adventure cards that double as pump spells have minor potential, but don't seem particularly exciting to me. Shepherd of the Flock // Usher to Safety is maybe good enough, but having to pick up your creature is way worse than the effects provided by SGods Willing or the now-rotating Sheltering Light. The 3/1 body for two mana is also not exciting anyone, except maybe some Blade of the Sixth Pride fans out there (I hear you, I see you, I haven't forgotten about you).
Ultimately, I think this deck will still be good, even without the upgrades. I think this is one of the current best decks in the format and it doesn't lose much, which speaks volumes to its future potential. With that said, this might be one of those decks that ends up being a product of its environment. When non-interactive strategies like Kethis, Nexus, Scapeshift and Golos rule the roost, Feather is a powerhouse, but in a new and slower format, it's anyone's guess.
The Ali Aintrazi-approved five-color Golos, Tireless Pilgrim strategy has been a solid recent addition to the Standard format. It's powerful, it's fun and it does cool things. What more could you want?
If you answered "mostly survive rotation" then I have good news for you. Believe it or not, this five-color mana base somehow survives four sets dropping out of Standard. Pretty unbelievable when a perfect three-color deck like Esper Hero can't even keep it together. Shame.
It loses the top end of Nexus of Fate, which is actually a massive loss. Golos can no longer just start taking extra turns while it makes loads of Zombies from Field of the Dead and effectively combo-kill people that way. With the power and speed of the format dropping and other decks taking a massive hit, that's probably not entirely needed anymore.
The biggest loss is Elvish Rejuvenator, which was the lynchpin of both this strategy and Scapeshift. However, Risen Reef is actually a completely legitimate replacement to Elvish Rejuvenator. It's less consistently good—you pretty much always want to hit land with Risen Reef before turn six—but it does offer a higher ceiling in that multiple copies do dirty things.
Does this deck gain cards from Throne of Eldraine, though?
Well it's a five-color deck looking for big and powerful effects, so yeah, I'd say it can gain something from pretty much any possible set they would print. Once Upon a Time looks sweet here as another way to find Field of the Dead or Golos, Tireless Pilgrim. Kenrith, the Returned King has some possible value as a Zacama-light addition to the deck. Realm-Cloaked Giant // Cast Off seems sweet as a wrath and big body. WW might be hard on the mana base, but this is exactly the kind of deck that's down to trounce with twelve mana worth of value.
If we're looking to go with a more white-based approach with Kenrith, Realm-Cloaked Giant and friends, then Harmonious Archon could also be nice. Personally, that's one of the cards I'm most excited to play with out of Throne of Eldraine, and this seems like exactly the kind of deck that could be a nice home for it. I think the Archon will end up being a strong card in Standard, and why not here? How bout some 3/3 Zombies? Now you're talking my language. English.
If the format ends up being fast red decks or black-red aggro decks, then Golos, Tireless Pilgrim is probably not going to be great. Let's say, however, that the format ends up being slower and grindier, with people trying to get value out of adventures and so forth. That sounds like exactly the conditions where Golos is prime to shine. This deck punishes those grindy strategies by grinding way harder than they ever could. It's pretty nice when every land drop produces 4 power and 4 toughness. With four fewer sets in Standard it's pretty likely that the speed of the format will drop, and thus it's pretty likely Golos will be a top deck.
One would think that this deck also takes a massive hit to the mana base, similar to Esper Hero. That actually isn't entirely true. While this deck also loses all the same check lands as Hero, Jeskai Walkers was never as reliant on those lands. It banked instead on Interplanar Beacon as a huge source of fixing, and that card does not rotate.
Additionally, all the Khans of Tarkir wedges like Jeskai, Abzan, etc. have an advantage over the Shards of Alara shards like Esper, Grixis, etc. The shards only have access to one Temple, while the wedges each have access to two. That's a real Shards are Nay from me. Having access to both Temple of Epiphany and Temple of Triumph will greatly improve consistency for this deck.
I don't know if this deck is in the market for another three-mana planeswalker, but The Royal Scions seems incredibly pushed for a three-mana 'walker. It starts at effectively 6 loyalty, only goes up, and you get to filter your hand every turn in a deck that snowballs once it gets going. It seems pretty darn good.
I could also see this deck being a strong home for a card like Stolen by the Fae. One of the issues for this deck is that if it falls behind, sometimes all it can do is keep playing planeswalkers every turn that just keep dying and it can't find a way to pull ahead. Stolen by the Fae is a massive tempo swing. You send your opponent's best creature packing and get a bunch of blockers to protect planeswalkers. Taking a turn off to do that could set up future turns incredibly well.
This deck loses almost nothing, gains a number of new cards from Throne of Eldraine and if the format slows down a bit, nothing grinds out an opponent like this deck does. I think it's fairly reasonable to believe that this will be the best deck in the format week one.