Here is a list of Standard format legal cards used in Pro Tour Rivals of Ixalan. I have not included some as I pulled the data only from the top decks. Those cards include a copy of Cast Out from the sideboard. It is quite interesting to see that Modern is quite healthy right now as the Top 8 decks have proven. It is also quite refreshing to see Standard format legal cards getting some plays in and out of the camera.
Check them out:
We have seen allied color fast lands from almost every deck in Modern format and it is no wonder that the enemy color is being used as well. Some include a one-to-three or a full set of it based on how they want it. Inspiring Vantage made it to the 75 of Burn deck to mitigate the loss of life compared to fetching a shock land. The other colors also have the same reason, especially midrange and control decks.
Concealed Courtyard is also from the enemy color set of fast lands printed in Kaladesh. B/W Eldrazi included a full set of it for the same reason as the others, to mitigate the loss of life.
When Blooming Marsh was first spoiled, most if not all of Abzan players included it to their 75. The deck needs to survive the first few turns and Blooming Marsh made sure that you no longer lose 5 life on your first turn by fetching an Overgrown Tomb to cast Thoughtseize. It's already a quarter of your life that you just lost, and when you're up against a Burn deck, I certainly guarantee that you will never win. If you do, call it a miracle.
Spirebluff Canal is also a new card included in decks like U/R Pyromancer that has a plan to make the battle go longer and U/R Storm when it started to switch into fetchless just to save huge amount of life.
Lantern Control was the deck that most players and viewers didn't expect to win Pro Tour Rivals of Ixalan just a week ago. Luis Salvatto included three copies of it for a higher chance of casting Ancient Stirrings on turn one. He also uses it to cast Whir of Invention without paying too much life via Spire of Industry, which is also currently a Standard format legal card.
The only deck that seems to abuse Inventors' Fair is Lantern Control. Aside from gaining a few life, it also has the ability to fetch an artifact from your library that you need to set up your game plan. This has been quite a good addition to the deck ever since it was printed.
Spire of Industry
Lantern Control and Affinity decks packed four copies of Spire of Industry as they help you cast colored spells since they depend heavily to their artifacts to win the game. With the help of Spire of Industry, both are now able to splash some colored spells that will help them win the game.
B/R Hollow One is the deck that almost everyone acknowledged as the breakout deck of the event. Dropping two Hollow One's on your first turn is possible as we have seen in camera and that pretty much spells an early defeat to the opponent if left unanswered. From the price tag of just a few cents, it is now sitting at $2 to $3 each but we expect that the price of Hollow One will never go beyond $5 for now since the card doesn't exist on other decks for the demand to increase.
Flameblade Adept is also a breakout card that is included in the B/R Hollow One deck. It is an uncommon printed in Amonkhet that only exist in this deck together with Hollow One. I'm not expecting for its price to spike hard but the foil copies of it might if it consistently displays it explosiveness for more upcoming big events.
Dropping Flameblade Adept on turn one followed by a turn two Goblin Lore or Burning Inquiry twice will display its raw power of dealing a minimum damage of 4 and possibly 7 damage at the maximum. It is also pretty much hard to block on turn two as the creature has the ability Menace which requires your opponent to have two creatures on the field before it can be blocked.
Glimmer of Genius
I have seen Glimmer of Genius being used by control players for the reason that you are able to scry twice before drawing two cards and that is quite a deep digging at instant speed. Anything else aside from that is yet to be discovered, maybe some blue-based Aetherworks Marvel deck in Modern soon.
Is Hostage Taker really worth it to be included in the 75 of a Traverse Shadow deck? It seems so as it can be used to deal with an opponent's creature or artifact. Based on what we have seen in the Pro Tour Rivals of Ixalan, it is definitely a good card that could steal an opponent's Ensnaring Bridge or Dark Confidant and cast it. It technically had the ability to twist the game on your favor.
Walking Ballista went to almost every format, from Standard to Modern, Legacy and even EDH/Commander format. It really shined well though in Modern as it has been a staple in Eldrazi Tron deck. Completing the Urza lands provides you the option to cast it for eight mana with Sanctum of Ugin providing the extra mana needed on your fourth turn. Sacrifice Sanctum of Ugin to get a much more destructive colorless creature such as Ulamog, the Ceaseless Hunger and you might be on your way to an easy win.
Liliana's Defeat is a card that you haven't seen that much in Modern but it seems that the pilot of the Grixis Control deck who put it on his sideboard means he wanted to deal with Death Shadow, Liliana, the Last Hope or Liliana of the Veil for the cheap price of one mana with the bonus of having your opponent lose 3 life if it deals with the latter.
I have seen Abrade used a lot in Standard and mostly included in red-based decks in Commander, but not in Modern. It seems the card has proven again its worth when it made its way in U/R Pyromancer's list to give the pilot the extra option to deal with problematic artifacts in the format like Ensnaring Bridge, Mox Opal and other artifacts that is needed to be dealt with in Affinity decks.
Kambal, Consul of Allocation
Kambal, Consul of Allocation got included in the sideboard of three competitive decks in Modern. Humans, B/W Eldrazi and Mardu Pyromancer include one or two copies of it probably to deal with U/R Storm as the deck heavily relies on non-creature spells and can't go all in when this creature is in play. The best deck that was able to utilize him so well was the 5-Color Humans since this creature also has a subtype Human.
Dire Fleet Daredevil
Dire Fleet Daredevil is a new card that came out from the set Rivals of Ixalan which is also a human that fits well in the 5-Color Humans deck. It's a sideboard material used mostly against midrange and control decks. Using an opponent's Thoughtseize from their graveyard to take away a card from their hand or an opponent's Collected Company to flood the board with your own creatures. There's a lot of potential targets for this card or even burn them with their own Lightning Bolt.
Kitesail Freebooter is the newest addition to the already existing Humans deck and it made the deck a bit more powerful. Aside from taking a non-creature spell from an opponent's hand, it also has Flying which is a bit hard to deal with sometimes. It can also go bigger than its usual 1/2 stats once Thalia's Lieutenant hits the battlefield and a bit more powered up by Noble Hierarch due to its ability Exalted that gives a creature +1/+1 when it attacks alone.
Unclaimed Territory is also a new addition to 5-Color Humans released from the set Ixalan a few months back and it made the deck less problematic with their manabase as the deck now have 12 source of lands that could produce any color as long as the spell is Human.
Gideon of the Trials
Gideon of the Trials is a white Planeswalker with the lowest casting cost coming out from Amonkhet. It hasn't seen that much play in Standard but in Modern, it has already been a part of U/W Control that has been quite a contender recently until B/R Hollow One deck beat them quick and easy. They really do have a hard time dealing with two Hollow One on turn one or the recurring Flamewake Phoenix and Bloodghast.
Settle the Wreckage
Settle the Wreckage is now the sweeper to go by U/W Control decks as they no longer have to tap out on their main phase on turn four just to deal with pesky elves, humans or any hyper aggressive decks. As long as their hand is not bothered by Thoughtseize, Inquisition of Kozilek or even Duress, the deck could deal with the messy battlefield on turn four.
Field of Ruin
They say Field of Ruin is the new Ghost Quarter of Modern and it seems true. Destroying a problematic land from an opponent's side while replacing the lands both of you lose is quite good. Ghost Quarter does the same thing but to be unable to replace your own land is quite a hard drawback especially if you won't draw enough lands after that.
The good old Opt, used widely in Standard and Modern format. The decks that used the card in Pro Tour Rivals of Ixalan are U/R Pyromancer, Grixis Shadow and U/R Storm. A good cantrip at instant speed at the cost of one blue mana that potentially digs two cards from the top of your library and replaces itself. Who doesn't want that? U/R Pyromancer seems to have efficiently abuse the card while Young Pyromancer is on the battlefied potentially connecting to another non-creature spell to gum up the board with elemental tokens.
Whir of Invention
When I first saw Whir of Invention, I knew that there will come a time that this card is going to be used well by a certain deck as it plays like Chord of Calling, except it fetches an artifact from your deck. I kept a few foils as I thought the demand for it will rise after a few years due to blue-based Commander players includes it on their decks and then, Luis Salvatto has proven that is also a great card on Lantern Control deck in Modern. Whir of Invention fetching an Ensnaring Bridge to keep the opponent's creatures at bay, holding them until he gets the pieces he wants to efficiently control them or directly fetching a Codex Shredder or some hate cards like Pithing Needle, Witchbane Orb or Grafdigger's Cage.
This is not something new but it is worth mentioning and should be included in the list as it is still a Standard-legal card. When Fatal Push first came out, almost every black-based deck include multiple copies of it. It helped Midrange and Control decks a lot to stabilize the board as early as possible. From what I've seen, it almost pushed out Elves, Naya Burn, Mono Green and other creature-based decks with a fast game plan. From the recent event, Pro Tour Rivals of Ixalan, the decks that include Fatal Push are Mardu Pyromancer, Abzan, Traverse Shadow, Grixis Shadow, Grixis Control, B/W Eldrazi and even B/R Hollow One have some copies in their sideboard.
Search for Azcanta
Of all the current Standard legal cards, Search for Azcanta has been my favorite and I'm quire most if not all control players feels the way I do. A two-mana Enchantment that could consistently filter the top of your library is like having a Sensei's Divining Top without paying anything at all. It also helps you fill your graveyard for a potentially unpayable Logic Knot, it turns into a land as well later and helps you dig for four cards except that it only gets you one non-creature spell. It's not actually a problem at all for Control players since they don't typically run a lot of creatures.