Manga and scans. Including lots of Hirano’s wacky pre-Hellsing hentai. Read more Hirano scanlations at Hiranomoe.
You might also be looking for Hellsing graphics or vampire literature.
Illustrations & Resources
Young King Ours illustrations
Text-free YKO Hellsing covers. A gorgeous, high-quality collection. Plus the “everyone is maids” drawing.
2002 Hellsing calendar
Compilation of the best scans I could find. Lots of random illustrations, including a young Alucard from 1443.
BESM Ultimate Fan Guide
Episode summaries, character profiles, worldbuilding, and speculation based on the TV anime.

Alucard’s Sigil
High-res image, 4620×5004 px, 288KB. (Script key.)

Bird of Hermes
Font face used in Hellsing titles. TTF file, 56 KB.
Translated Hirano Manga
Coyote
WWII-era hentai featuring proto-Pip and proto-Major.
Full version
Hentai-free version
The Legends of Vampire Hunter
Hentai short, a prototype of Hellsing Order 01 with a black-haired proto-Seras.
Hellsing: The Dawn
Canon backstory of Hellsing, with Walter and Girlycard.
Chapter 1
Chapter 2
Chapter 3
Chapter 4
Chapter 5
Chapter 6

Desert Guardian (“Captain’s Story”)
WWII-era hentai short about a proto-Captain. (Wildly offensive, but included here for completeness.)
Clean version
Most scanslating by The Birds of Hermes. The Dawn 2-4 by frozen_drops; 5 by ATU-BOTI; 6 by Hiranomoe. Desert Guardian by Hiranomoe.
Raw Hirano Manga
Angel Dust: Revenge Bible
Hentai story where a teal-haired nun is rescued from abuse by a proto-Anderson.
Chapter 1
Chapter 2
Chapter 3
Doc’s Story
Hentai short in which a proto-Doc, working for Hitler, summons a catgirl demon named Azmodeus.
Daisoutou Sabasaba
More hentai. Some Nazis capture a catgirl. You can see where this is going.

Dai-Doujin Monogatari (Volume 1)
A story about a would-be mangaka and the secret organization out to get him. Features several prototypes of familiar faces.

Hirano Miscellaneous
Covers and panels from random, increasingly-old Hirano works.
Shine-Relevant Miscellaneous
Please, Jeeves
A faithful, funny, fanmade manga adaptation of a P. G. Wodehouse short story.
Chapter 1
Chapter 2
Chapter 3
Research Notes