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: “Inevitably when its prey looks up to the sky it pounces”
Content: The shadow of a bird.
Writing: Some serious OSR ambush predator energy.
Art/design: Well-organized table layout.
Usability: Don’t look up. 

Concept: “A new religion has arisen in the desert. Worshiping the Unnamable God of Names, blaspheming against SHE and HE, promising the revolt. Galgenbeck has sent its inquisitors.  The half-giant Nephilim walk the earth. If you join them, almost certain death awaits.”
Content: An escalating tower crawl of nameless gods and religious conflict. Complete with three new classes, gear, artifacts, angels, Nephilim, and mythical creatures. 
Writing: An absolutely metal reinterpretation of Jewish history and folklore.
Art/design: A spectacle of artistic styles as varied as the tower of tongues.
Usability: Visual styles delineate sections. VTT resources available. 

Concept: “This horse sized cadaver-like bird moves soundlessly, sneaking into bed chambers at night to inject the sleeping with paralyzing venom”
Content: A bird, who paralyzes, and always wins initiative. 
Writing: Yet more proof that nice names usually denote horrible creatures.
Art/design: Screenshot and discord text.
Usability: Probably inspired by someone's Elden Ring nightmares. 

Concept: “As you put on the cape, feathers start growing from under your skin...”
Content: A cape to become the bird of your dreams (or at least omens).
Writing: A surprisingly flexible and self-regulating magic item with gut-wrenching descriptive text.
Art/design: Some winged angel, tastefully protected by some boxed text.
Usability: Make sure to emphasize the bone-crunching transformation. 

Concept: “Rugged tunnels far beneath the dirt of the earth. What stirs in the dark with all-seeing eyes, beaks, and claws, scratching the stone?”
Content: An escape dungeon, full of feathered “friends”.
Writing: Social elements add a dynamic element to the dungeon.
Art/design: Top-down map and creature illustrations highlight a compact two-page dungeon reference.
Usability: Compact and organized for easy reference of the entire dungeon during play. 

Concept: “Lurking at the edge of your perception, a primal hatred made manifest.”
Content: Worse than your standard-issue goose, this one has a paralyzing stare
Writing: Truly expresses the sentient malice in the heart of every goose
Art/design: Portrait and cool colors emphasize the fowl-beast’s the soulless frigidity
Usability: Geese are jerks

Concept: “Enter the pest house, fight past the screaming corpses, find patient zero, and hopefully live to see another miserable week.”
Content: A good doctor’s mistake, Galgenbeck’s problem.
Writing: A highly volatile plague crawl, full of pressure, pus, and projectile vomiting.
Art/design: A sturdy top-down manor illustration in a forest of text, with the occasional pink and yellow highlight.
Usability: Highlights emphasize frequently referenced monsters and mechanics.