Art of Magic: Heretical Pacts

From publisher blurb: The warlock's time has come. Art of Magic - Heretical Pacts brings you a host of new options for the fifth edition warlock. From six new patrons, such as Baalzephon and the elements themselves, to new pact boons, 10 new eldritch evocations, 5 feats, 4 warlock items, and 18 new spells, you’ll find a host of diabolical options to make you the most bad-ass character in any party.