30 cards where the card types include “planeswalker” and the colors is B

Liliana, Dreadhorde General (Foundations #176)
Vraska, Betrayal's Sting (Phyrexia: All Will Be One #115)
Liliana, Death's Majesty (Midnight Hunt Commander #121)
Liliana of the Dark Realms (Magic 2014 #102)
Professor Onyx (Duskmourn: House of Horror Commander #153)
Liliana of the Veil (Dominaria United #97)
Tevesh Szat, Doom of Fools (Commander Legends #153)
Lolth, Spider Queen (Adventures in the Forgotten Realms #112)
Sorin Markov (Magic 2012 #109)
Ob Nixilis, the Hate-Twisted (War of the Spark #100)
Ob Nixilis Reignited (Duskmourn: House of Horror Commander #152)
Sorin of House Markov // Sorin, Ravenous Neonate (Modern Horizons 3 #245)
Sorin of House Markov // Sorin, Ravenous Neonate (Modern Horizons 3 #245)
Sorin, Imperious Bloodlord (Innistrad Remastered #133)
Liliana, Heretical Healer // Liliana, Defiant Necromancer (Commander Collection: Black #1)
Liliana, Heretical Healer // Liliana, Defiant Necromancer (Commander Collection: Black #1)
Liliana Vess (Magic 2015 #103)
Valki, God of Lies // Tibalt, Cosmic Impostor (Kaldheim #114)
Valki, God of Lies // Tibalt, Cosmic Impostor (Kaldheim #114)
Liliana, Waker of the Dead (Core Set 2021 #108)
Liliana, Untouched by Death (Core Set 2019 #106)
Liliana, the Last Hope (Double Masters 2022 #81)
Sorin the Mirthless (Innistrad: Crimson Vow #131)
Ob Nixilis of the Black Oath (Commander Masters #176)
Liliana, Death Wielder (Amonkhet #275)
Davriel, Rogue Shadowmage (War of the Spark #83)
Ashiok, Wicked Manipulator (Wilds of Eldraine #78)
Liliana, Death Mage (Core Set 2021 #328)
Vraska, Scheming Gorgon (Rivals of Ixalan #197)
Liliana, the Necromancer (Core Set 2019 #291)
Sorin, Vampire Lord (Core Set 2020 #290)
A-Sorin, Imperious Bloodlord (Core Set 2020 #A-115)
Davriel, Soul Broker (Jumpstart: Historic Horizons #15)

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