Hellboy Comic Bundle for $18 has

Hellboy v1: See of Destruction (own)
Hellboy v2: Wake the Devil 2E (own)
Hellboy v3: The Chained Coffin and Others 2E (own)
Hellboy v4: The Right Hand of Doom 2E (own)
Hellboy v5: Conqueror Worm 2E (own)
Hellboy v6: Strange Places (own)
Hellboy v7: The Troll Witch and Others (own)
Hellboy v8: Darkness Calls (own)
Hellboy v9: The Wild Hunt (own)
Hellboy v10: The Crooked Man and Others (own)
Hellboy v11: The Bride of Hell and Others (own)
Hellboy v12: The Storm and the Fury (own)

Hellboy in Hell v1: The Descent
Hellboy in Hell v2: The Death Card

Hellboy and the BPRD: Her Fatal Hour
Hellboy and the BPRD: Long Night at Goloski Station
Hellboy and the BPRD: The Beast of Vargu
Hellboy and the BRPD: The Seven Wives Club

Hellboy Winter Special
Hellboy Winter Special 2017
Hellboy Winter Special 2018
Hellboy Winter Special 2019

Hellboy: 25 Years of Covers
Hellboy: All-Seeing Eye
Hellboy: An Assortment of Horrors
Hellboy: Into the Silent Sea
Hellboy: Krampusnacht
Hellboy: Weird Tales (own)

Hellboy: Odd Jobs (tpb story anthology, not graphic novel, own)
Hellboy: Emerald Hell (tpb novel, not graphic novel, own)
Hellboy: Oddest Jobs (tpb story anthology, not graphic novel, own)

Ghost/Hellboy Special
Hellboy vs Lobster Johnson: The Ring of Death
Itty Bitty Hellboy
Young Hellboy: The Hidden Land

Hellboy v1 to v12 is very good and in general good pulpy magic/occult/mythos action. Certainly seems quite worth it just for the stuff I don't have, though I also don't have anything in electronic format.