When entering the locked door on the Isle of Ashes, open the chest to the right, just inside the door. Do not click on the book — this will take you to the next part of the game. Instead, go back through the door and enter the Verhoffin Ruins. Do not enter the doors. You are not strong enough to kill the skeletons in there. While in here, go down the hall and around the corner to the end and open the chest. Take everything and leave. Go back to the now opened door and look at the chest. It should now be closed. Re-open it and take everything. Go back to the ruins, leave ruins, go back to chest, and the chest will be closed again. Keep going backwards and forwards collecting items from same chest. Note: This was done with the v1.2 patch of the game.
There are two chests in the area where the old woman will give you the Dragonfly quest. One is at the end of the Dragonfly Cave and the other is inside the keep (door which could not open). Go inside the ruin castle and exit to get to the loading screen. Those chests will now be reset and filled with items, spells, skills, and items. This can be repeated as many times as needed. Note: This was done with v1.0 of the game.
Go to Thjorgard Training Hall. Fall down the chandelier and go west. Break the crate where the black chest is located and get the artifact. Leave through the door with all the lizards and return. A different powerful artifact will be there every time.