So far we have:
Reason Unknown or Unstated: (76, 7, 4, 13, 11 & 58819003613051935406)
The way it looks: (8, 19, & 11)
Related to personal info: (9)
Involves math: (120, 69, 216, 11, & 10)
Related to person's life: (13, 45, & 4)
Pop culture reference: (42)
One person dislikes even numbers and one dislikes odd numbers except those ending in 5
11 is the most popular at 3 votes, it even got one ("eleven") vote
And among reasons given, math is the most popular
I asked this question because I was guessing that numbers (being visual and symbolic) would be popular among Aspies, but I guess they aren't that big a deal to most of us. But thanks for answering everyone!
PS, if anybody has any other symbols they are fond of, I'd be interested to see those too. Thanks.