Steve Jackson Games: In-Nomine
The official, Satanized for your protection, website.

Asmodee: INS/MV
The original, French, version.

Amadán's In Nomine
A surreal collection of David Edelstein's finest work -- including writeups for potential-canon Superiors and Servitors.

Annotations
The maniacal workings of Eric Alfred Burns. The Man. The Myth. The Madman behind Alaemon: Demon Prince of Secrets for Superiors 4: Rogues to Riches.

Jo's In-Nomine
A collection of stories, campaigns, npcs, and those cursed movie trailers by Jo Hart!

Morgan's In-Nomine
Though it suffers from having a vastly inferior layout and design, the content is anything but that. I'll be sure that Morgan goes far, and that he signs Arcangel's contract with his own blood.

Fiat Justica Ruit Caelum
An ongoing online campaign run by Genevieve "Maya" Cogman, set in the sleepy city of Washington D.C. (Recommended Reading!)

In Nomine: 2070
Phillip J. Moyer's vision of the great beyond. For they are Humanity's last, best hope.