Concept: “‘They are often seen before Miseries befall the world, leading many to believe them to be agents of Verhu, Nechrubel, or some other malevolent entity.”
Content: Relatively benign; may transfer Omens from players to the GM, and feathers allow PCs to re-roll low Omen rolls (at a cost)
Writing: Mostly mechanics with concise description of behavior
Art/design: Monochrome silhouette suits the monster concept
Usability: Additional in-game lore, inspiration, and hooks provided on the product page 

Concept: “What happens when the lore of our world collides with the Dying World of MÖRK BORG?”
Content: The first volume of collected FÖLK-LORE Jam entries
Writing: Varies by author, see individual entries under the FÖLK-LORE Jam tag
Art/design: Varies by entry; single-page entries are well balanced in spreads
Usability: Varies by entry, but it’s all Mörk Borg—how tough could it be?