Good times!
1. Portable mobile battery charger. I play music more or less constantly, so the battery is always at risk of running low while I'm out somewhere.
2. Keys, wallet, phone. I don't want to put them in my pockets or carry them in my hands, so in the bag they go.
3. Tylenol and Advil. Not so much for me, more for friends and rando gals who express the need for one.
4. Tissues and wet wipes. I used to live in Mexico and learned the hard way to always carry a backup supply of papel higiΓ©nico.
5. At least one working pen (gel, broad point). I don't trust other peoples' pens like that.
Honorable Mention: If it's a D&D night, my minis and my iPad take up the most real estate.