I dont have a passport or drivers license (long story). However I have an OHIP card. As per the LSAC requirements (https://www.lsac.org/lsat/taking-lsat/lsat-test-center-admission-requirements/identification-accepted-lsat-admission) a valid ID must contain ,a recent and recognizable photo of you, your first name, your last name, your date of birth. My health card contains all of this. However this may seem foreign to the proctor so I wonder if anyone has experience using a OHIP card for the flex test.