This page of AC Valhalla Dawn of Ragnarok guide shows the locations of all Cosmetic Schemes appearing in Vangrinn region.
Location: the western part of the map, right next to the border with Svaladal.
You will find this scheme on a wooden table in a locked room. You're going to need your companion to access this one. This location is best accessed during a raid, as there are supplies in the room that have to be picked up in order to complete this activity.
Location: southwest of the region, east of the synchronization point.
The scheme lies on a small meadow, right next to a small tree. Its location is clearly visible. If you can't find it on your own, use Odin's Sight (R3 on consoles/V on PC)
Location: southern part of the map, next to the synchronization point.
To get to this scheme you must direct the light beams so that they eventually point to an area above the door. To do this, place the first statue so the ray is directed to the other statue located beyond the lava. Use Power of Muspelheim to be able to step onto the lava and shoot the shields so that the ray is reversed.
Once the ray is pointed to a right location, the door will open. The scheme is right next to them, on your right.
Location: west of the border with Eitir, just below the synchronization point.
To get to this diagram you must first enter the cave. To access it, you'll need to destroy the ice - to do so, use a melee weapon or a bow. Once inside, use the Power of Muspelheim in order to be able to cross the lava stream safely. The scheme lies at the end of the hallway, right next to the teleportation point.
Location: on a small island, in the southern part of the location.
To access the location with the scheme, you're going to need a key. The key is carried by a guard that patrols the nearby area. We recommend a stealth kill so that the alarm isn't raised. Use the key on the door and find the scheme. It lies next to a large wooden table.
Location: Draupnir Smida
You will find this diagram right next to the Mythical Memory, it lies on a small stone right next to the wall.