I spent my school years known as Pico X because there was always more than 1 with my name in my class. Though I did go to a girls' school, so that must double your chances if that being an issue.
We are waiting for DC2 to arrive. We really like a top 10 girls' name, but don't want to inflict the same on our baby (who won't go to a single sex school). How far down the list do we need to go to minimise the duplication risk?