Here's an aura that works whenever something is within range...
Mind Freeze Aura (Su): At the end of each of a frostwind virago's turns, creatures within 30 feet of her must succeed on a DC 30 Will save or be shaken for 1 round. Those who fail by 5 or more are dazed for 1 round, and those who fail by 10 or more are stunned for 1 round. The save DC is Charisma-based. A frostwind virago can suppress this ability at will as a free action. Frostwind viragos are immune to this aura.
And another...
Insidious Aura (Su): A remmanon emanates a telepathic aura that plays on the doubts and fears of its foes. Opponents that begin their turn within 30 feet of a remmanon must succeed on a DC 26 Will save or suffer the effect of a confusion spell for that round. An affected foe never treats a remmanon as the nearest creature for the purpose of determining the confusion effect. The save DC is Charisma-based.
A remmanon and allies within 30 feet of it gain a +4 bonus on attack rolls against opponents affected by this aura.