Phone, purse and keys. Surely anything else can be left at home?
If I'm nipping to the shop around the corner maybe but for everyday life, no way.
Headphones to listen to music/podcasts/drown out the screaming kids on the bus/train on the way to work. They live in a small pouch with my powerbank and usb cable.
Paper diary bc I am old school and need to write things down or I don't remember them
Make up bag with perfume/lipbalm/brush/bobby pins/concealer etc for touch ups during the day
Pouch with tampons/pads - if it's actually during my period I will have the pouch with more than one but I also keep a couple of emergency tampons in my make up bag at all times, both in case of surprises (I have PCOS so periods can surprise me at any time) but also in case a friend ever needs one in an emergency.
Water bottle - I always try to keep my water bottle in my bag so I never go thirsty.
Book for when I know I will be sitting around - waiting for an appointment, on the train etc - but don't want to be constantly satring at a screen
Small pouch with a personal first aid kit - couple of plasters, alcohol wipes, hand gel, paracetamol, my medications
And two glassses cases - one has my sunglasses (I have light sensitivity so even weak sunlight can sometimes make my eyes hurt) and the other has either my glasses or a set of my disposable lenses in.