You can get the Dragoncrest Shield Talisman at the Bestial Sanctum. You can get here by travelling through Caelid or by using a teleport in the small lake north of the Third Church of Marika ...

Head over to the Godskin Duo area and make your way to the Dragon Temple Altar Site of Grace. Then, go through the pathway ahead leading to Maliketh’s Liar. The Dragoncrest Shield Talisman +2 ...

Wearing this talisman increases your damage reduction to all sorts of Physical Damage by 17%. While it's similar to the Dragoncrest Greatshield Talisman, you can't use both simultaneously.