45 cards where the card is in the modern deck/cube and the card types include “planeswalker”

Ajani, Mentor of Heroes (Journey into Nyx #145)
Ajani Vengeant (Duel Decks: Ajani vs. Nicol Bolas #1)
Ashiok, Nightmare Weaver (Theros #188)
Chandra, Awakened Inferno (Core Set 2020 #127)
Chandra, Torch of Defiance (Kaladesh #110)
Domri, Anarch of Bolas (War of the Spark #191)
Elspeth, Knight-Errant (Modern Masters #13)
Elspeth, Sun's Champion (Theros #9)
Garruk, Apex Predator (Magic 2015 #210)
Garruk, Primal Hunter (Commander 2019 #167)
Garruk Relentless // Garruk, the Veil-Cursed (Innistrad #181)
Garruk Relentless // Garruk, the Veil-Cursed (Innistrad #181)
Garruk Wildspeaker (Commander 2011 #157)
Gideon, Ally of Zendikar (Battle for Zendikar #29)
Gideon Jura (Magic 2012 #16)
Jace Beleren (Magic 2011 #58)
Jace, the Mind Sculptor (Masters 25 #62)
Jace, Vryn's Prodigy // Jace, Telepath Unbound (Magic Origins #60)
Jace, Vryn's Prodigy // Jace, Telepath Unbound (Magic Origins #60)
Karn Liberated (Ultimate Masters #5)
Karn, Scion of Urza (Dominaria #1)
Koth of the Hammer (Duel Decks: Venser vs. Koth #44)
Kytheon, Hero of Akros // Gideon, Battle-Forged (Magic Origins #23)
Kytheon, Hero of Akros // Gideon, Battle-Forged (Magic Origins #23)
Liliana, Dreadhorde General (War of the Spark #97)
Liliana, Heretical Healer // Liliana, Defiant Necromancer (Magic Origins #106)
Liliana, Heretical Healer // Liliana, Defiant Necromancer (Magic Origins #106)
Liliana of the Veil (Ultimate Masters #104)
Liliana, the Last Hope (Eldritch Moon #93)
Nahiri, the Harbinger (Shadows over Innistrad #247)
Narset, Parter of Veils (War of the Spark #61)
Nicol Bolas, Dragon-God (War of the Spark #207)
Nissa, Vastwood Seer // Nissa, Sage Animist (Magic Origins #189)
Nissa, Vastwood Seer // Nissa, Sage Animist (Magic Origins #189)
Nissa, Vital Force (Kaladesh #163)
Nissa, Voice of Zendikar (Oath of the Gatewatch #138)
Nissa, Who Shakes the World (War of the Spark #169)
Ob Nixilis Reignited (Commander 2019 #124)
Ral, Izzet Viceroy (Guilds of Ravnica #195)
Saheeli Rai (Kaladesh #186)
Sarkhan the Masterless (War of the Spark #143)
Sorin, Grim Nemesis (Shadows over Innistrad #251)
Sorin, Solemn Visitor (Khans of Tarkir #202)
Tamiyo, the Moon Sage (Avacyn Restored #79)
Teferi, Hero of Dominaria (Dominaria #207)
Ugin, the Spirit Dragon (Fate Reforged #1)
Vivien Reid (Core Set 2019 #208)
Vraska, Relic Seeker (Ixalan #232)
Wrenn and Six (Modern Horizons #217)
Xenagos, the Reveler (Theros #209)

The message was clear to Sorin—time to search for something else.