46 cards where the colors is B and the set is “ori”

Blightcaster (Magic Origins #85)
Catacomb Slug (Magic Origins #86)
Consecrated by Blood (Magic Origins #87)
Cruel Revival (Magic Origins #88)
Dark Dabbling (Magic Origins #89)
Dark Petition (Magic Origins #90)
Deadbridge Shaman (Magic Origins #91)
Demonic Pact (Magic Origins #92)
Despoiler of Souls (Magic Origins #93)
Erebos's Titan (Magic Origins #94)
Eyeblight Assassin (Magic Origins #95)
Eyeblight Massacre (Magic Origins #96)
Fetid Imp (Magic Origins #97)
Fleshbag Marauder (Magic Origins #98)
Flesh to Dust (Magic Origins #280)
Gilt-Leaf Winnower (Magic Origins #99)
Gnarlroot Trapper (Magic Origins #100)
Graveblade Marauder (Magic Origins #101)
Infernal Scarring (Magic Origins #102)
Infinite Obliteration (Magic Origins #103)
Kothophed, Soul Hoarder (Magic Origins #104)
Languish (Magic Origins #105)
Liliana, Heretical Healer // Liliana, Defiant Necromancer (Magic Origins #106)
Liliana, Heretical Healer // Liliana, Defiant Necromancer (Magic Origins #106)
Macabre Waltz (Magic Origins #107)
Malakir Cullblade (Magic Origins #108)
Mind Rot (Magic Origins #281)
Nantuko Husk (Magic Origins #109)
Necromantic Summons (Magic Origins #110)
Nightmare (Magic Origins #282)
Nightsnare (Magic Origins #111)
Priest of the Blood Rite (Magic Origins #112)
Rabid Bloodsucker (Magic Origins #113)
Read the Bones (Magic Origins #114)
Reave Soul (Magic Origins #115)
Returned Centaur (Magic Origins #116)
Revenant (Magic Origins #117)
Sengir Vampire (Magic Origins #283)
Shadows of the Past (Magic Origins #118)
Shambling Ghoul (Magic Origins #119)
Tainted Remedy (Magic Origins #120)
Thornbow Archer (Magic Origins #121)
Tormented Thoughts (Magic Origins #122)
Touch of Moonglove (Magic Origins #123)
Undead Servant (Magic Origins #124)
Unholy Hunger (Magic Origins #125)
Weight of the Underworld (Magic Origins #126)

In the blink of an eye, they strode from deep snow to the end of this search.