回複：學生證

You're still in F-1 status during OPT period.

Whether or not your student ID is still good depends on your school's policy. Mostly you may not use it to continue any benefit on campus if you're not currently registered. When using ID anywhere else without checking school's registration information, it only depends on acceptance of other party and/or the expiration date on the ID (or registration card), which is normally ok in your situation.