I would highly recommend any and all of Christian Eichhorn's Mörk Borg supplements - they all have fantastic layout and art, creative content that adds new systems and creative twists on existing ones, and capture the brutal and beautiful feel of the core book.
Galgenbeck Sacrifice is a great pick-up if you're looking for a sprawling, in depth campaign through Galgenbeck - story, systems, hooks, encounters, dungeons, and enemies included (. Sacrifice also includes plenty of fun to bring to your own sessions, such as rumours and quests, NPCs / enemies, and a D100 encounter table.
Enjoy Galgenbeck Sacrifice? Check out Bergen Chrypt, which also provides a huge campaign through the the Wästland. Want something to complement Sacrifice? Check out Purgatory or Apocrypha for more general gameplay supplements/additions.