Each of the four lords areas contains a couple of special items, which are unique in the way that they can only be found once per playthrough. They are usually worth a decent amount of Lei, so they can be worth keeping an eye out for.
The Village contains several unique treasures scattered across optional areas and side paths.
Location: Found sitting in a box inside the basement of the house with a well in front near the Maiden of War.
Reward: Teddy Bear worth 3500 Lei.
Notes: The door to the basement will be broken after escaping from Castle Dimitrescu.
Location: Found inside closet with the combination lock inside Luthier's House.
Reward: Steel Hræsvelgr worth 14000 Lei.
Notes: Requires the Luthier's Key to enter the house.
Location: Found inside a crypt near Castle Dimitrescu at the location marked "Riverbank Treasure House".
Reward: Golden Lady Statue worth 20000 Lei.
Notes: Requires the Crank and Boat Key as you will be able to sail there the bridge area near the Lone Road. You will also have to solve a small puzzle about lighting the fires in the room.
Location: Found inside a cave near a computer and some explosives.
Reward: Antique Coin worth 8000 Lei.
Notes: Requires the Crank and Boat Key, as you will have to sail there from the bridge near the Lone Road.
Location: Found inside a chest near the exit of Otto's Mill.
Reward: Father Nichola's Angel worth 22000 Lei.
Notes: Requires the Six-Winged Unborn Key to enter the area with Otto's Mill (sidepath on the way to The Stronghold).
Location: Found at a small altar near the end of The Stronghold.
Reward: Guglielmo's Plate worth 25000 Lei.
Notes: The treasure is marked on the map as Treasure Under the Stronghold.
Castle Dimitrescu includes a few unique treasures found in early-game rooms and optional side areas.
Location: Found on the desk after being captured.
Reward: Crimson Glass worth 3500 Lei.
Location: Found in one of the cells in the dungeon (Chamber of Solace).
Reward: Ingrid's Necklace worth 2000 Lei.
Location: Found in a locked dresser after defeating Bela (the first daughter you will defeat)
Reward: Wooden Angel Statue worth 3000 Lei.
Location: Found near the body of Donna Beneviento once you defeat her.
Reward: Angie worth 28000 Lei.
Location: Found in the grave of Cladia Beneviento.
Reward: Berengario's Chalice worth 18000 Lei.
Notes: Can be obtained by bringing the Broken Slab to her grave, which is found near the Graveyard area after completing the Beneviento Villa (otherwise the crypt with the Broken Slab will be closed).
Location: Found inside a chest on boat in the initial area after Salvatore Moreau lair once he has been defeated.
Reward: Silver Angel Statue worth 10000 Lei.
Location: Found on a table in the control room just before the Cargo Bay.
Reward: Cigar worth 3000 Lei.