Stories set earlier in the B.P.R.D. universe:

• Dark Horse Comics’ B.P.R.D. (Platinum Age) – A History of Comics Index
• Dark Horse Comics’ B.P.R.D. (Golden Age) – A History of Comics Index
• Dark Horse Comics’ B.P.R.D. (Interregnum) – A History of Comics Index
• Dark Horse Comics’ B.P.R.D. (Silver Age) – A History of Comics Index
• Dark Horse Comics’ B.P.R.D. (Bronze Age) – A History of Comics Index
• Dark Horse Comics’ B.P.R.D. (Dark Age) – A History of Comics Index

Hellboy: Seed of Destruction (1994) 1-4

[One Shot] Hellboy: The Wolves of Saint August (1995)

‘The Chained Coffin’ [[One Shot] Hellboy: The Chained Coffin and Others (1998)]

• Abe Sapien ‘Subconscious’ [Dark Comics Presents (2014) 11]

Hellboy: Wake the Devil (1996) 1-5

Hellboy: Almost Colossus (1997) 1-2

‘Abe Sapien versus Science’ [[One Shot] B.P.R.D.: Hollow Earth and Other Stories (2003)]

‘The Right Hand of Doom’ [[One Shot] Hellboy: The Right Hand of Doom (2000)]

Hellboy: Box Full of Evil (1999) 1-2

‘Being Human’ + ‘The Ectoplasmic Man’ [[One Shot] B.P.R.D.: Being Human (2011)]

Hellboy: Conqueror Worm (2001) 1-4

The Visitor: How and Why He Stayed (2017) 1-5

See: Hellboy Elseworlds/Spinoffs – A History of Comics Index

See: DARK HORSE’2002: B.P.R.D. Cycles – A History of Comics Index