The Stars' Design is a random drop from mobs in Suramar.
There is a quest item that pretty much one shot mobs in The Athenaeum, Moon Guard Stronghold.
The item provided is a trap that stuns mobs in an AOE and does massive damage after a short delay.

Lay Waste, Lay Mines

The method is primarily used to farm the hidden artifact design, but there might be some other uses for this, such as Darkmoon Faire - Grisly Trophy.
Avoid Nightborne invaders and constructs as they do not drop anything.

Rest of the mobs however, drop silk, leyblood, various boe, and vendor jun

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