This guide will utilize pictures, and go chapter by chapter including every collectible within that chapter.
This guide will cover the collectibles for each chapter, in the order they appear, so that you can easily scroll one chapter at a time as you play and get all the different items in each one, without having to watch / read 3 different guides every time you play.
The collectibles are Gifts, Curiosities, and Hugo's Herbatorium flowers. There are also the Alchemical Carts, which will be covered as well, and isolated achievements that I will also include since they appear in specific chapters.
This guide does not cover more general achievements like crafting or story related ones, there are plenty of guides out there for those.
Chapter 1 - The de Rune Legacy
Gift 1 - Duck Whistle
After the beginning sequence of the hunting trip with your father, look left and go to the Stables. The stable on the farthest left has a ladder. Go up it, and the Whistle is waiting there.
Isolated Achievement: More Practice
From the main castle gate where you start the chapter, go straight and take a right at the wall. Go through the structure to the back yard of the stable, to where the targets (vases sitting out in a row on barrels), are waiting and destroy them all.
Curiosity 1 - Spices
After entering the main entryway of the house, go right. You will go through a dining hall, and into a storage room. There is a ladder there just before the door to the kitchen. Go up it, and along the walkway to the far left where the Spices wait on a table.
Curiosity 2 - Tablecloth
From the main entryway of the house, go left. Go up the spiral stairs, and follow a NPC servant named Louise to your room (First door on the left). The Tablecloth is on your bed.
Chapter 2 - The Strangers
Gift 2 Amulet
Immediately after reaching the village, before the market stalls, go right along the river. There will be a pier built over the water, go down it. To your left will be a necklace on the planks near a post.
Curiosity 3 Soap
While in the village, go over the bridge. If you go right just after the bridge into a small alleyway, you will enter a small courtyard. There will be a interaction with a NPC in a window, and a chicken coop with dead chickens. In the back corner on a small table are the soap.
Isolated Achievement: Feeding the Hungry
After you reach the area of the town where white Xs are painted on the doors, turn right and go down that street adn take the first right you come across. The apple tree is in a yard on the left.
Curiosity 4 Incense
In Clervie's home, upstairs in the bedroom where you change your clothes. It is sitting on a table to the left by the window.
Chapter 3 - Retribution
Gift 3 Rosary
Within the church before you climb the ladder. Turn right at the altar and it is on a table just on the left before the barricade.
Flower 1 - Carnations
Hard to pass by, as it is directly in your path and Hugo goes to them immediately upon seeing them. When you go into the courtyard chasing after the Monk, they will be growing beside the pile of chopped logs.
Curiosity 5 Brew
Within the catacombs of the church, just after you set the brazier swinging. As you follow the swinging brazier, about mid-way, there is a hidden entrance on the right. Hop over the planks and it is inside in front of a window, in a big pot.
Curiosity 6 Crusader's Tabard
When you and Hugo get separated, you will meet again in the room full of rats where you have to knock down and light various braziers. Once you meet Hugo again, go back up the ladder he came down from. Ahead of you slightly to the right will be a box containing the tabard.
Chapter 4 - The Apprentice
Curiosity 7 - Hermetic Vessel
At the beginning of the chapter, go right to the lake. Follow the lake past the pier until you get to a small campfire. To the right of the campfire is a tree stump, with this item beside it.
Isolated Achievement: Hide and Seek
Sneak up on Hugo while he is hiding in the orchard. Do this by going far left after he runs off, and go through the trees until you see him crouching. Come up behind him and interact with him for this achievement.
Gift 4 - Alchemist Diary
After Hugo runs away into the orchard, go to the far right to the lake shore. Within a broken rowboat will be the diary.
Flower 2 - Aquilegia
Once you finally reach the farmhouse, before going inside, go around the back. The Flower will be growing beneath a tree.
Chapter 5 - The Raven's Spoils
Flower 3 - Gladiolus
At the beginning of the chapter, follow the path up to the battlefield. After the characters speak, turn around and go back. You will not be able to go back the way you came, but on your right is a path. Cross the creek and take the uphill path and hug the cliff wall. Stay as far right as you can and you'll come to a downhill slope. At the end of the path is the flower. You may have to run back a bit to get Hugo to come to you after you find the flower. He will not follow you until you locate it first.
Curiosity 9 Sickle
When you come up to the cart with the brazier on it that you have to push, instead of going straight push the cart to the left. In a back area will be a single soldier, and this item in a chest. Remove the soldier, take the item, and push the cart back to where you started to resume the story.
Curiosity 10 Oliphaunt
After you knock down the two hanging bodies to distract the rats, go left around the wooden palisade and there is a chest hidden in a small alcove back there. This item is laying on the ground to the left of it.
Isolated Achievement Savior
Just after the Oliphaunt curiosity, go inside the siege tower. There will be a soldier trapped at the back of it. Stick the torch in the torch holder on your right, and use a Ignifer with your slingshot to light the torch on the wall next to him.
Gift 5 Ballastella
In the area where you direct Lucas to operate the catapault with the attached burning basket, after Hugo retrieves the stick, light the stick and go right to the stone fence there. Within this fence is a bonfire that you can light, more sticks, and this item beside the bonfire.
Chapter 6 - Damaged Goods
Gift 6 - Knucklebones
After the 2nd distraction, while in the tent with the bottles and sleeping guards, go left after the first section with 2 sleeping guards. On the table there will be this item. There is a guard that patrols around so watch for him before going to the table.
Curiosity 11 - Pound Sterling
Before entering the canteen / cafeteria area, go right and look under a wooden tower for this item. It will be sitting on a table near the back
Curiosity 12 - Declaration of War
After you free Hugo and are sneaking through the camp. From his cage, go left through the lumber yard. You are going to have to kill soldiers in your way. The white open sided tent is where you want to go, the item is on a stool.
Chapter 7 - The Path Before Us
Curiosity 13 - Horseshoe
After the crossing the mill wheel, near the crafting bench, turn right to see an opening in the wall. Destroy the lock with your sling and climb in the window. The horseshoe is hanging on the wall.
Flower 4 - Hawthorne
After you leave the mill, while going through the destroyed village. In the very last house in the back is this flower.
Curiosity 14 - Map
While sneaking through the soldiers, in the second area on the far right is a open sided white tent. The map is on the table there. Two guards with helmets will have to be killed.
Alchemist Cart 1
Unmissable, story related. Lucas teaches you how to make Luminosa to access it.
Gift 7 - Vinegar
After entering the start of the castle, turn left when the path splits. Have Melie unlock the door. The vinegar is straight in front of you on a table.
Chapter 8 - Our Home
Curiosity 15 - Iconography
At the start of the chapter, instead of following Hugo go right up the broken stairs.
Isolated Achievement - Tribute
Instead of going into the laboratory, go down the stairs and into the crypt beyond.
Gift 8 - Alchemical Crucible
After visiting Lucas in the laboratory, follow Hugo again. Go through the door to the right of the starting area, past the work bench. To your right is a overgrown alcove with the gift just at your feet.
Curiosity 16 - Bird Language Manual
After talking to Melie, behind the barrel.
Flower 5 - St John's Wort
After the cutscene where you hang the necklaces on the tree, to the left. Hugo is kneeling beside it.
Chapter 9 - In The Shadow of the Ramparts
Flower 6 - Lavender
Immediately at the start of the left, run forwards and left. Beside a fallen tree is the Flower.
Curiosity 17 - Sheepskin
In the room where you have to knock down the hanging body to distract the rats, in the back room to the left of the stairwell is a chest and within it is this item.
Curiosity 18 - Piece of Transis
In the cemetary, after you trap the rats and can access the wheeled cart, go over the wall behind it. look for the white stain that indicates you can go over. To your left at the bottom will be a crypt with this item.
Alchemical Cart 2
Just after the wooden bridge and the guy that was throwing dead bodies into the water, get to the area with the two guards and then go into the alley on the left. You will need Luminosa to get past the pit of rats.
Near the main gates, go to the right where the two soldiers went. Kill them both. The item is on the table.
Isolated Achievement - The Hard Way
Go through the main gate of the University instead of the side entrance. Kill both the guards and interact with the door to unlock the achievement.
Chapter 10 - The Way of the Roses
Flower 7 - Daisy
After the library where you find out what color book you are looking for, you will enter a second library with two soldiers looking for it. There will be one of the light projectors and the first rats you've seen so far in this chapter. Release the rats onto the soldiers. In the cubby hole where they were hiding is the flower.
Curiosity 19 - Study of a Skinned Person
While following Rodric and the guards escorting him, you go into a room full of chairs in rows on either side of a central path. On the right side of the room, this item is on one of the chairs
Curiosity 20 - Theriaque
While solving the puzzle in the secret underground library, in the back left side there is a hidden room with this item on a table within it.
Gift 10 - Reading Stone
After Rodric's 2nd stealth kill, to the right of the door way / crate of helmets is a table with this item on it.
Alchemist Cart 3
In the University courtyard, BEFORE entering the burning library itself, go across the courtyard straight ahead behind the hedges, and turn right. You will need Luminosa to get past the rat pit.
Chapter 11 - Alive
Flower 8 - Rhododendron
When you go to investigate the symbols with Rodric, head instead to the right of where he is standing and into the outer right before the brazier. This flower is there.
Chapter 12 - All That Remains
Gift 11 - Calamus
Inside the house opposite of Lucas and his beam of light. Throw Odoris to the left near the wagon, and Ignifer onto the bonfire to access it.
Isolated Achievement - Merciful
When you and Hugo are using the lamps to navigate the path of rats, you will come across two soldiers. DO NOT break the lamps lighting them up. Talk to them, and then move on, use Odoris to get through the first soldier's group of rats, and then again for the second soldier's. You will need to use Luminosa to kill the 2nd group of rats. (Otherwise they kill you during the opening the door animation)
Curiosity 21 - Harnois Helmet
After you encounter the body of your father and the huge swarm of rats, go right once you get handed the torch. Go through the opening, and head left. You will pass the body of two servants. In the room with the female servant's body and the shields on the wall, go to the back right corner inside a box to find this item.
Flower 9 - Cinquefoil
After exiting the house, it is left down a path before you go down the stairs.
Alchemist Cart 4
Before using the cart with the Brazier upon it, turn to look behind you. Use Ignifer to light the fire in the distance and Luminosa to destroy the rats, then run to the cart. You can use the light beam to navigate back. You can tell Lucas to stay so he doesn't risk getting eaten by rats and setting you back at checkpoint.
Curiosity 22 - Family Tree
Once you enter the dark laboratory, go right. There on a table is this item.
Chapter 13 - Penance
Curiosity 23 - Ragdoll
At the very end of the path between the houses, on the left, is a house with a broken door. The doll is in a crib on the right hand side of the room
Curiosity 24 - Knight Figurine
Before going and interacting with Hugo, right and through the door on the right. It is sitting on a table in there.
Flower 10 - Daffodil
After freeing Hugo, look to two trees on the right. Hugo will run to it when you get closer.
Chapter 14 - Blood Ties
Flower 11 - Nightshade
In the back right area from where you entered, in a little garden behind some hedges.
Isolated Achievement - Captain Sidekick
In order to get this achievement, you must beat the Captain into the hallway after the garden, otherwise he closes the door on you and you will not get the achievement. You do this by getting through the garden before he does, and waiting for him within the room under the cadaver table.
Chapter 15 - Remembrance
Flower 15 - Rockfoils
At the beginning of the chapter, take the door closest to Lucas. Turn right.
Chapter 16 - Coronation
Alchemist Cart 5
After you split up from Melie and Lucas, and you have Rodric kill the remaining soldier, head down the road to your right. You will come across a door with a white X on it, and a fence with a white cloth draped over it. Turn right. At the end of the path go left, kill the guard, and the Alchemist Cart is there at the end of the road.
Curiosity 25 - Discipline
After you free the rats for the first time and use them to kill two guards, turn and look right from where the guards were standing. There is a small alley there. Go down it and to the left, this item is beside a dead guard.
Flower 13 - Christmas Rose
After the battle where Rodric starts breaking down the door and the soldiers rush you, kill them all. Go through the big doors opposite you that the guards had come through. At the very end of the path is this flower.
Isolated Achievement - The Blacksmith
Where you encounter the two prisoners being held by the guards. Kill the guards, then go right. Turn right at the burning fire into the alley filled with rat nest, and break the lock on the door with your sling. Go back to where you first entered the courtyard, and the door you just unlocked will be right ahead of you. Go through it. Rodric will start running when you get close.
Curiosity 26 - Inquisitors Manual
After killing the annoying group of guards before the cathedral gates, go to the right of the gallows. Behind a barrel is this tiem.