I surely believe that there are people who have the traits that are now labeled as traits of an indigo child, and it is probably becoming more common for people in recent generations to have these traits. For now, I don't believe any of the further speculations, especially those that have than new age spirituality flavor to them.
Here are these attributes of an an indigo child that I have found, along with how much I relate to them
2=Mostly 1=Somewhat 0=Not Really
They come into the world with a feeling of royalty (and often act like it) - 1
They have a feeling of "deserving to be here," and are surprised when others don't share that. - 2
Self-worth is not a big issue. They often tell the parents "who they are." - 2
They have difficulty with absolute authority (authority without explanation or choice). - 2
They simply will not do certain things; for example, waiting in line is difficult for them. - 2
They get frustrated with systems that are ritually oriented and don't require creative thought. - 1
They often see better ways of doing things, both at home and in school, which makes them seem like "system busters" (nonconforming to any system). - 2
They seem antisocial unless they are with their own kind. If there are no others of like consciousness around them, they often turn inward, feeling like no other human understands them. School is often extremely difficult for them socially. - 2
They will not respond to "guilt" discipline ("Wait till your father gets home and finds out what you did"). - 2
They are not shy in letting you know what they need. - 2
*Here are the quiz results for the auras too, though it is a misconception that the concept of indigo children is based off of auras:
Red - 2
Orange - 2
Magenta - 4
Yellow - 0
Logical Tan - 3
Environmental Tan - 1
Sensitive Tan - 0
Abstract Tan - 3
Green - 5
Blue - 0
Violet - 6
Lavender - 6
Crystal - 1
Indigo - 5
Red Overlay - 0