Immortality (self) – The ability to live forever.
Belasco (Marvel) is a supervillain that has only lived since the 13th century (Official Handbook of the Marvel Universe V2 #2)!
Cain and Abel (DC) relive a tale of murder again and again (Who’s Who in the DC Universe #1).
Eternal Warrior (Valiant) is a superhero that has lived and fought for thousands of years (Eternal Warrior V2 #1).
Immortal (Image Comics) is a superhero that has this power and in many ways is a good guy version of Vandal Savage (The Official Handbook of the Invincible Universe #1).
An interesting narrative about immortals among in The Sandman: Brief Lives V7 (Vertigo).
Vandal Savage (DC) is a supervillain that has lived for fifty thousand years!
Mortigan Goth (Marvel) wins immortality in a chess game with Mephisto in Mortigan Goth – Immortalis #1.
Deathwish (Malibu) has cancer and is immortal and this character predates Deadpool by four years (1993 SkyBox Ultraverse).
Inquisitor – Creature Collection I
Punk Mambo – Valiant Universe Handbook 2016 Edition #1 (2016)
Doctor Mist (DC) finds that immortality is a curse in Secret Origins – Zatara & Zatanna V2 #27.
Mawdryn – Fifth Doctor Sourcebook
Pulp Sci-Fi – “Water of Life” – 2000 AD #1098
Vector 13 – “Case Ten Thrillkill” – 2000 AD #974
Yancy Queeg – Outcasts #1 (DC)