There are, as of the Ghost Phase (December 2013 - January 2014), 25 rewards that may be won in AvA. These 25 rewards span everything from the overall VP winner to regional rewards. With a few exceptions, Alliances must have had at least five participants in AvA to qualify for the rewards. Rewards are usually distributed within 48 hours after the end of a phase, and can include anything from seals to unique titles that cannot be acquired any other way. Rewards are distributed to every Alliance member who is in the Alliance when the rewards are given out, and participated in AvA for that phase.
Alliances may only receive one reward per phase. An Alliance will receive the highest reward they qualify for. The rank of rewards is the order in which they are shown when clicking the Rewards button.
A full list of rewards may be viewed by going into the Alliance window, clicking on the War Map tab, then clicking on the Rewards button.