Amulet of Teamwork

This silver chain comes together in the form of a pair of linked hands. 

This amulet allows you to work more effectively as part of a team. When you use the "Help" action on your turn, that ally can then add your proficiency bonus to theirs for attacks made on that turn. Also, when you flank an enemy, you and any allies also flanking that target gain a +2 to damage.