For my last couple shows, I had a small snap-lock box (like a larger tupperware with handles), that held in it a few essentials (like tissues, couple bandaids, hand sanitizer, lotion, post-its, pens/pencils, etc). It was nice to have something for my actors to go to if they had forgotten a writing utensil, or just needed a bandaid for their heels or a small cut, without having to lug out the heavy duty first aid kit. It certainly wasn't as extravagant as a professional stage manager's would be, but it worked for what I needed.