This is the Holy Symbol of Ravenkind from the D&D 5e adventure Curse of Strahd. I modeled this directly from the image shown on page 222 of the adventure book, and intend to hand it out to my players when they eventually find it.

It's designed to be printed on a resin printer at 0.05mm layer height, though should also work well on FDM. The finished size is 80mm x 80mm x 10mm, and prints flat without supports. The center is sized to take a 12mm stick-on crystal, and has a loop on the side to string a chain or ribbon through.