My original Esper list is getting modified too much, to the point that it's almost not Esper any more, so rather than completely shred that list, which is rather disfavored by the current meta, I decided to build a separate Blue/White version that should hopefully be geared a bit more towards the present meta game.
Deck Overview
U/W Spirits is an aggressive tempo deck designed to apply quick pressure to your opponents while at the same time slowing down their game plan and creating card disadvantage for them. Most of the creatures in the deck have flying, which makes them quite difficult to block for most modern decks. While not as explosive as humans, as soul crushing as Tron, or as inevitable as U/W Control, U/W Spirits can still be highly competitive so long as you know how to play the deck and keep an eye out for meta appropriate micro adjustments.
Card Choices
Creatures
Mausoleum Wanderer: The first of the three incredible gifts offered by Eldritch Moon, Mausoleum Wanderer does everything that this deck wants to do. It can come down on Turn 1 and immediately begin pressuring the opponent, can grow absurdly big without much effort, and in the late game can counter an important piece of removal, a key combo piece, or an otherwise obnoxious board wipe. For all of these reasons, running 4 copies of the Wanderer is a no-brainer.
Spectral Sailor: This card is the real deal. I know many spirits players have moved past running this unassuming card, but sailor can provide a ton of value for a U/W spirits list. It's another 1 mana 1/1 flying spirit, which is fine in the early game to apply pressure or pump Mausoleum Wanderer. It has flash, meaning that you'll never have to tap out on your turn to play this; drop it after a board wipe to rebuild, in response to a must-counter spell to let you counter it with wanderer, or create a surprise blocker. Plus, spirits often suffers from running out of resources in the late game, and sailor provides a repeatable mana sink to draw new cards. 4 mana is a lot for 1 card, but not requiring the sailor to tap and letting you hold up mana to either draw or cast other creatures is quite useful. Sailor isn't something I feel needs to be run as a 4-of, but a pair of these guys definitely helps the deck's functionality and consistency.
Rattlechains: When I first saw this card when Shadows Over Innistrad was released, I couldn't believe how much they'd packed into one card. For 2 mana, you're getting a 2/1 flyer that can be played at instant speed. Not only that, but when it enters the battlefield it can protect one of your other important spirits from being removed by giving it hex proof until the end of the turn, often creating an easy 2 for 1. And, as if that weren't enough, as long as Rattlechains is on the battlefield you can cast any other spirits in your hand at instant speed. This card just does it all. While it may not have had the support it needed when it was first released, Modern has a ton of great spirits that can make Rattlechains an absolute beating. This is another easy 4 of in the deck.
Unsettled Mariner: Prior to Modern Horizons, Thalia, Guardian of Thraben was our go-to for taxing effects to slow down our opponents. While not a perfect replacement, Mariner is an excellent upgrade from Thalia. Not only does it technically have the right creature type, but it can also stack its effects, given that it isn't a legendary creature. Additionally, it can really punish targeted effects like Walking Ballista, along with serving as a solid road bump against removal heavy decks; notably, this is amazing for hampering Burn, Jund, and U/R prowess decks, all of which want to be efficiently casting interactive non creature spells. The lack of evasion can make it an awkward draw when you need to squeeze through some damage, so I've cut my list down to 3 copies in the mainboard, but there's a 4th copy in the sideboard, because it's good enough that you'll want 4 copies in many matchups.
Supreme Phantom: This is what helps the deck really come together. Following up a Turn 1 Mausoleum Wanderer with a Supreme Phantom is one of the best openings you can have, as it applies a quick clock to the opponent while also making the Wanderer a more potent Counterspell option. Dropping Phantom in with Aether Vial or Rattlechains can mess up opposing blocks or present lethal damage where it was lacking before. Finally, having 2 Phantoms out immediately puts both creatures outside of Lightning Bolt range, an important fact given the current prevalence of Arclight Phoenix decks. I can't ever see a situation in which you wouldn't want to be running 4 copies.
Selfless Spirit: Another gift from Eldritch Moon, Selfless Spirit is one of those cards that I really think gives Spirits the nod over something like Humans. Whereas Humans get stonewalled pretty hard by Trong playing Oblivion Stone or other decks deploying sweepers like Anger of the Gods or Supreme Verdict, Selfless Spirit can turn those traditional answers into relatively weak, mana inefficient 1:1s. Even when you're not getting value out of its sacrifice effect, a 2/1 flyer for 2 that can easily be pumped is still golden in this deck. Unfortunately, the meta is currently rather unfriendly to Selfless Spirit, so I've cut it down to 3 copies currently, which still might be too many.
Shacklegeist: M21 was a bit of a letdown in terms of its spirits offerings...or so it seemed at first. Shacklegeist is actually a solid addition to the spirits toolbox, giving you a creature with flying that survives Plague Engineer and Liliana, the Last Hope. Plus, an ability to tap down an opposing creature without needing to spend mana is fantastic against decks reliant on singular big creatures. This can stop Uro, Titan of Nature's Wrath, Kroxa, Titan of Death's Hunger, Primeval Titan, and Wurmcoil Engine, among others. Plus, it's just another good early play to apply flying pressure on your opponent's life total. I've seen some lists running this as a 4-of, but I'm not quite sold on that yet. In the meantime, I've added a pair to the deck for extra flexibility.
Spell Queller: The last, and perhaps the greatest, gift from Eldritch Moon, Spell Queller is an absurd card. a 3 mana 2/3 with flying and flash would already be a decent card, if not good enough for constructed. Giving it a relevant creature type and letting you exile a card on the stack just makes it an unbelievably good card. Queller can help you exile removal spells, board wipes, combo pieces, and more, while at the same time presenting a solid flying threat. Of course, it can feel like a blowout if it gets removed and your opponent gets to cast their exiled cards for free, but hopefully by that point you're ahead enough that it won't matter. And if you're not, you probably weren't winning that game anyways. You should always be running 4 copies of this in the main board.
Drogskol Captain: The original Lord for spirits. Captain is still great, due to its ability to pump your team while at the same time making other spirits immune to your opponent's removal spells. However, it's not statted quite as well as Supreme Phantom, making it more vulnerable to removal even if you have it and a Phantom in play. If you land two Captains, however, your opponent essentially can't interact with your board any more, making it extremely deadly. Even though the deck can feel a bit clunky with too many 3 drops, Captain's effects are strong enough that you'll rarely be unhappy about drawing into it, making it another playset for the deck.
Skyclave Apparition: I was honestly not expecting a card like this in Zendikar Rising. In actuality, this has the potential to be the best new inclusion for the list since Supreme Phantom. For 3 mana, you get a 2/2 that can exile most problematic threats in the format. It doesn't matter if they're creatures, artifacts, planeswalkers, or enchantments, this can hit any of them as long as they're not tokens and have CMC of 4 or less. Plus, this permanently gets rid of the offending card. If your opponent does remove the apparition, they get a dinky vanilla creature with no evasion. Speaking of evasion, this spirit lacks flying, which is a bit of a bummer, but it's ultimately not a major issue. It still helps tap creatures with Shacklegeist, triggers Mausoleum Wanderer, and can be protected by Rattlechains and Drogskol Captain. The spirit tag here is very important. Plus, with a few lords, this can be a rather scary creature even on the ground. I'm starting on two of these in the main deck and another in the sideboard. I wouldn't be surprised if the list actually wants 4 copies, but for now I think having too many 3 drops is problematic, so I'm banking on only main decking a pair to supplement the deck's removal package.
Noncreature Spells
Aether Vial: It's pretty simple. Spirits is a fast, creature based deck. Vial lets you put out creatures quicker and at instant speed without exposing them to counter magic. Vial should be played as a four of in every deck like this.
Path to Exile: The best white removal spell in modern, Path is a great way to efficiently deal with creatures regardless of how big they are, and it doesn't cause death triggers. Given how creature heavy the modern meta game is currently, running 4 copies of Path seems to be the correct decision.
Sideboard
Blessed Alliance: This is a great, versatile card to run in your sideboard. It can provide crucial life gain against burn decks or kill problematic single attackers, including Bogles, Hexproof infect creatures, Reality Smasher, Inkmoth Nexus, Blinkmoth Nexus, and all kinds of other creatures. Many people still don't (or can't) play around this, making it a fantastic sideboard option. I've heard plenty of people comment on its lack of efficiency, and I understand the argument. Theoretically you could get better value for some of this card's modes with something else. But, the versatility is why this card is so good. We have a finite number of sideboard slots, and being able to cover multiple rolls with a single card is invaluable.
Damping Sphere: This is primarily a method of keeping Tron in check, though it also has solid application against Amulet Titan, Eldrazi decks, and Storm. It can be cast with mana of any kind, and often a turn 2 Damping Sphere can give you enough time to pull out a win before they're able to deal with it.
Disdainful Stroke: There are many strong cards that cost 4 or more mana, whether in Trong, U/W control, or Primeval Titan based decks. Force of Negation is generally better at dealing with important noncreature threats, but running a single copy of Disdainful Stroke can help you out against certain matchups.
Kira, Great Glass-Spinner: Even with Rattlechains and Drogskol Captain, sometimes you want to protect your creatures even more. Kira can do a nice job of forcing your opponents to spend multiple spells to remove your creatures while even protecting herself. She's not a card you want multiple copies of, but she's decent as a 1 of.
Rest in Peace: Even with Hogaak, Arisen Necropolis and Faithless Looting banned, graveyard decks are still something to plan for. Rest in Peace is one of the single best graveyard hate cards that has ever been printed, and is an easy inclusion in the sideboard.
Declaration in Stone: This is here mainly for two matchups: token decks, and Dredge. Go-wide token decks are hard to interact with, especially ones that run Lingering Souls. The flying token creatures are a nightmare for spirits to push through. Meanwhile, dredge has some absolutely absurd starts, flooding out with multiple Bloodghasts, Prized Amalgams and Narcomoebas. While Rest in Peace can ruin dredge completely, adding in another good counterplay never hurts. Declaration lets you exile every copy of the target creature that your opponent controls, meaning that you can neuter a dredge player's deck if they were aggressive enough to dump out a ton of their creatures onto the board. Declaration might not be the best card around, but it's pretty good at what it does.
Spirit of the Labyrinth: This is a card that I feel like I need some testing with, but it sounds great in theory. A ton of decks right now are running cantrip cards and/or Uro, Titan of Nature's Wrath, and this shuts off the card advantage from those cards. Its 3/1 stat line is excellent to push aggression, but does leave it vulnerable to removal. Fortunately, as a spirit, we can protect and buff it in several different ways. I'll have to get some games under my belt, but this spirit seems like it can shine in this meta game.
Brazen Borrower: Ah Borrower, how you've fallen. At one point you were a core card in the deck, but with Skyclave Apparition on the horizon, you're just not as important now. Nevertheless, the fact that Borrower can offer a relatively cheap instant speed bounce effect against any non land permanent while setting itself up to push damage later makes it fairly appealing. I can't really justify more than a single copy currently, but it should still do its job against decks where the opponent has to tap out for a single big card.
Sideboard Guide (Work in Progress)
Mono Green Tron: -4 Spell Queller, -2 Spectral Sailor, +2 Stony Silence, +2 Damping Sphere, +2 Disdainful Stroke
Eldrazi Tron: -2 Spectral Sailor, -2 Path to Exile, -2 Force of Negation, -2 Selfless Spirit, +2 Stony Silence, +2 Damping Sphere, +2 Blessed Alliance, +2 Disdainful Stroke
Burn: -2 Deputy of Detention, +2 Blessed Alliance
Jund: -4 Aether Vial, -2 Force of Negation, +1 Kira, Great Glass-Spinner, +1 Celestial Purge, +2 Rest in Peace, +1 Thassa, God of the Sea, +1 Declaration in Stone
Whirza: -2 Spectral Sailor, -2 Selfless Spirit, +2 Stony Silence, +2 Rest in Peace
U/W Stoneblade: -2 Force of Negation, -2 Path to Exile, +1 Thassa, God of the Sea, +2 Blessed Alliance, + 1 Geist of Saint Traft
Titanshift: -2 Deputy of Detention, -2 Spectral Sailor, +2 Disdainful Stroke, +2 Blessed Alliance
Edit 9/4/2020: Significant changes made to the list, but will update card choices and other information later. After Zendikar Resurgent releases, I plan to move the 2 copies of Brazen Borrower to the sideboard, replacing the two Spirit of the Labyrinth, and replacing them with Skyclave Apparition, with a 3rd copy of the Apparition replacing Deputy of Detention in the sideboard.
Edit 9/13/2020: Updated the card choice guide and set the deck to reflect its status after the release of Zendikar Rising. I'll still need to update the side boarding guide.
