Some common topics that I like to address:
-how will you bring diversity to this campus -- not just race, gender, orientation, but diversity of thought, experience, and perspective
-a big challenge you've faced -- anything, either childhood, personal, professional, clinical
-what have you done - since graduation and what you'll be doing if you have a gap year
-why our school -- check the school's you're applying to, some have this question
-anything else you want to tell us -- for red flags, most leave this blank
-why medicine -- many schools have an additional question like this, you can focus it on your future pathway
-underserved -- a time you worked with someone different than you, some schools have a questions specifically asking about racism or the underserved, but this type of response can "fit" many prompts
-teamwork -- a time you worked with a team towards a goal, some prompts focus on difficulty in a team like a time you disagreed
-clinical -- always good to have a strong clinical anecdote on hand, this one is flexible and can be used in many places