From this guide page to Dungeons & Dragons Dark Alliance you will learn what's the use of the various items you can find during the game - Tablets, Tomes, Reliefs, Paintings.
As you play D&D Dark Alliance, you can find additional collectibles on all maps, including Tablets, Tomes, Reliefs and Paintings.
These items develop the plot of D&D Dark Alliance and allow players to explore the history of Icewind Dale and Forgotten Realms. Collecting story items is not mandatory and does not involve unlocking new equipment.
Collecting story items is required to for the trophy Now It Makes Sense and thus for winning the platinum trophy in D&D Dark Alliance.