EastScape Wikibuilt from the game itself

Void seeds

Where to find it: The Boneyard (The Understudy), Cloudreach (Angel of Minor Inconvenience), The Carnival (The Grinning Man), The Thunderhead (Storm Golem; The House), The Deep Wild (Grim Lich; Vault Warden), The Vault (Vault Warden; Coin Hoard; The Last Dealer), The Wilderness (Vault Warden), Starfall Rift (Crater Wisp; The Sevenfold Conjunction).

“Plant them on your island. They grow the flower that element's ink is brewed from.”

Dropped by

MonsterLevelHow manyChance a killRoll
The Sevenfold Conjunction1296–10AlwaysEvery kill
Crater Wisp1201–38.8%One of the table
Grim Lich6612.5%Own roll
The Understudy381–20.8%Own roll
Angel of Minor Inconvenience481–20.8%Own roll
The Grinning Man721–20.8%Own roll
Storm Golem521–20.8%Own roll
The House701–20.8%Own roll
Vault Warden741–20.8%Own roll
Coin Hoard861–20.8%Own roll
The Last Dealer921–20.8%Own roll
Bone Golem (deeper)381–20.8%Own roll

Grows

Plant it on your island's plots (Harvesting 45): ready in about 180 minutes, logged in or not.