American Gods by Neil Gaiman
Norse Code by Greg van Eekout
The Gospel of Loki by Joanne M. Harris
Wild Card (Etudes in C# Book 1) by Jamie Wyman
Hunter Sacrificed (Wild Hunt) by Nancy Corrigan*
*Nancy has a second Norse-themed series called Elemental Desire also.
I Bring the Fire: Parts I, II, III, & In the Balance: (A Loki Series) by C. Gockel
The Unleashing (Call Of Crows Book 1) by Shelly Laurenston*
*Shelly has a second Norse-themed series called The Gathering also.
Very Much Alive: True Destiny, Book 1
The Elsker Saga by S.T. Bende*
*S.T. Bende has a second Norse-themed series called The Ære Saga also.