Hello!
I'll go in the order of your list:
1) Shirts/Uniforms/Outfits
Our team has seperate uniforms for competitions; the pit crew has pit shirts, that have a chest pocket and button over our regular uniforms, and the spectating team members wear their regular team uniform (a T-Shirt). We don't have a mascot... But for our homecoming parade, we have an electric go-cart that pulls our robot cart... I don't know if you'd consider that a mascot or not (we don't bring it to competitions).
2) Headgear
Our team has had hats in the past... But a team we were allianced with in an off-season event had silver sequin fedoras with blinking LED's! They also had silver wigs.
3) Accessories
We have a rah-rah box, which contains pom-pons in our team colours, hair spray that sticks your hair in a specific way, along with other cheering materials.
4) Buttons/Other Handouts
We have buttons. We also have pamphlets containing information about our team (I'd like to say that I love when teams have buttons; I'm trying to cover my team uniform with them by the end of 2013).
5) Pit Design
We have a dry-erase board that we write the times of our matches on, along with the teams that are in our alliance. We also have an LED marquee that we put "Good luck to everyone" on.
I hope this helps you. I love super-spirited teams, because they're fun to mingle with!
