CR 17+ undead creatures from Monster Labs. These public stat blocks fit that band of the table; remix the CR or abilities if your party is ahead of the curve.
Tacky Lich
CR 30 · Undead
Frostreaver, the Frozen Lich
CR 30 · Undead
Calarax The Lich King
CR 30 · Undead
Aeris the Lich
CR 27 · Undead
Vanita, Daughter of Dracula
CR 26 · Undead
Mindflayer Dracolich
CR 24 · Undead
Gargantuan Ghost-Skeleton
CR 23 · Undead
Archlich
CR 21 · Undead
Lord Drake, King of the Fallen Heroes
CR 20 · Undead
Hydra Dragon Vampire Hybrid
CR 20 · Undead
Pudim Fantasma
CR 20 · Undead
The Forgotten Archmage
CR 20 · Undead
The Nameless One
CR 20 · Undead
Death
CR 20 · Undead
Collector
CR 20 · Undead
Illirikum, Tyrant of the Cycle of Life and Death
CR 20 · Undead
Primordial Soul Hunter Titan
CR 20 · Undead
Persona Thanatos
CR 20 · Undead
Erandys D'Vol
CR 20 · Undead
Rimuru Tempest, the Lich
CR 20 · Undead
Vormut, The Golden Lute Dracolich
CR 20 · Undead