Charting the Unknown adds ten bosses to Crimson Desert, spread across the mainland, Demeniss and the islands of the Great Ocean, and seven of them are fought as part of a quest.
The other three, the Knight of Void, Satyros and Reggis the Isleguard, come with a location and nothing else, so those are the ones to go looking for on your own. Everything else is tied to a questline, which means your story progress decides when you can fight them. Here’s the full set, grouped by where they live.
The mainland
Four bosses sit in the Crimson Desert region itself.
Knight of Void: the Buried Corridor in Trivana Sound, behind an illusory wall.
Kharzek, Archon of Antumbra: the Silent Burial Ground, fought during Kliff’s “Veil of Darkness” main quest.
Scrap Metal Queen Stoneback Crab: Trader’s Expanse in Varnian Territory, fought during Oongka’s “Unidentified Attack” main quest.
Iron Tyrant Harkan: same spot and same quest as the crab.
The Knight of Void is the only one of the four without a quest name attached, so the illusory wall in Trivana Sound is the thing to hunt for. The crab and Harkan share a location and a quest, which means one trip to Trader’s Expanse covers both.
Demeniss
Geago the Flamecrazed is the lone boss here, waiting at Scorchrock Castle and fought during Damiane’s “Chasing a Shadow” main quest. That quest is how you get to him, so push it forward if you’re stuck.
The Great Ocean
The water holds the other five, spread over four islands.
The Dancing Catfish Crusher: Samora Island, fought during “The Seaborne Village” faction quest.
Satyros: Satyros Waterfall Village on Satyros Island, in the southwest of the South Sea.
Reggis the Isleguard: Razanui Bone Nest, northeast of Razanui Island, which sits in the ocean’s southwest.
Rohan Cooper: Bergel Island, fought during the “Cave of Sorrow” faction quest.
Leviakan: Bergel Island, fought during the “Catastrophe of Ancient Times” faction quest.
Bergel Island has two bosses from two different faction quests, so if you’re there for one it’s worth checking whether the other is open yet. Satyros and Reggis are the two you can sail straight to without a quest pushing you.