From the DMsGuild product page:
The Frostmaiden has come to claim Icewind Dale!
Haughty, overbearing, mercurial, uncaring, and fickle, Auril is not a benevolent goddess waiting to shower the world with warmth and compassion. Like the winter she ushers in and controls, the Frostmaiden is cold, dangerous, and unpredictable. She is an evil goddess who allows, and even finds joy in, her most devout followers sacrificing, tormenting, and persecuting her enemies.
Not only is Auril creating problems in Icewind Dale, but now you can unleash her cultists to wreak havoc in Ten-Towns!
Extensive Information on the Church of Auril for your Rime of the Frostmaiden game!
This product features:
Descriptions of cult beliefs, behaviors, and rationale
16 new spells
2 new magic items
6 new NPC/creature statblocks
Over 12 new ways to add cultists and cult activity to the area
23 pages of useful content!