There is a ton of comics from Mignola in my library but I really don't know what to pick.
Just noticed the above bit from your initial plea. Not knowing what your catch-as-catch-can collection looks like, if you don't want to pick up a new comp, best I can offer is this list of HB stories in order of publication that I fabbed up for a friend:
OMNI 1 - SEEDS OF DESTRUCTION (94p)
OMNI 1 - THE WOLVES OF SAINT AUGUST (40p)
CSS v1 - THE CORPSE (25p)
OMNI 1 - THE CHAINED COFFIN (10p)
CSS v1 - THE IRON SHOE (6p)
OMNI 1 - WAKE THE DEVIL (117p)
OMNI 1 - ALMOST COLOSSUS (46p) [June, July]
CSS v2 - A CHRISTMAS UNDERGROUND (21p)
CSS v2 - HEADS (10p)
CSS v2 - THE BABA YAGA (6p)
OMNI 2 - THE RIGHT HAND OF DOOM (10p)
CSS v2 - THE VAECOLAC (12p)
CSS v2 - GOODBYE MISTER TOD (8p)
OMNI 2 - BOX FULL OF EVIL (43p)
CSS v1 - PANCAKES (2p)
CSS v1 - THE NATURE OF THE BEAST (8p)
CSS v1 - KING VOID (14p)
OMNI 2 - CONQUEROR WORM (124p)
OMNI 2 - THE THIRD WISH (56p)
CSS v2 - DR. CARP'S EXPERIMENTS (13p)
CSS v1 - THE PENANGGALAN (8p)
CSS v2 - THE TROLL-WITCH (10p)
CSS v2 - THE GHOUL (11p)
OMNI 2 - THE ISLAND (65p)
CSS v2 - MAKOMA (48p) Mignola w/ Corben
CSS v2 - THE HYDRA AND THE LION (10p)
OMNI 3 - DARKNESS CALLS (150+p) Duncan Fegredo
CSS v2 - THAT THEY GO DOWN TO THE SEA IN SHIPS (24P) Jason Shawn Alexander
CSS v2 - THE VAMPIRE OF PRAGUE (19p) P. Craig Russel
CSS v2 - THE CROOKED MAN (72p) Richard Corben
CSS v2 - IN THE CHAPEL OF MOLOCH (24p)
OMNI 3 - THE WILD HUNT (200+p) Duncan Fegredo
CSS v2 - THE BRIDE OF HELL (24p) Richard Corben
CSS v2 - HELLBOY IN MEXICO (28p) Richard Corben
OMNI 3 - THE STORM (72p) Duncan Fegredo
CSS v2 - THE WHITTIER LEGACY (8p)
CSS v1 - DOUBLE FEATURE OF EVIL (28p) Richard Corben
CSS v2 - THE SLEEPING AND THE DEAD (48p) Scott Hampton
CSS v2 - BUSTER OAKLEY GETS HIS WISH (24p) Kevin Nowlan
OMNI 2 - BEING HUMAN (28p) Richard Corben
OMNI 3 - THE FURY (77p) Duncan Fegredo
CSS v1 - HOUSE OF THE LIVING DEAD (49p) Richard Corben
CSS v1 - HELLBOY VS THE AZTEC MUMMY (8p)
OMNI 4 - HELLBOY IN HELL, Book 1
CSS v1 - THE MIDNIGHT CIRCUS (49p) Duncan Fegredo
CSS v1 - HELLBOY GETS MARRIED (16p) Mick McMahon
CSS v1 - THE COFFIN MAN (8p) Fabio Moon
CSS v1 - THE COFFIN MAN 2 (8p) Gabriel Ba
OMNI 4 - HELLBOY IN HELL, Book 2
OMNI 2 - INTO THE SILENT SEA (49p) Gary Gianni
Book designations on the left are just there to reflect what he had on hand.