Been a while since this was necessary:
A LARGE folding tote like this https://amzn.eu/d/06Usq96Q (inside the hospital holdell), to shove everything in to make a quick get away on discharge. also handy if you move beds or to shove any outside coats in under the bed. A small folding shopping bag (or two) for laundry/shower/randomness.
Power bank, multicharger 2 cables.
Small squeezy squash when it was short unpredictable admissions, large when regular longer admissions
A variety of cup-a-pasta/couscous type things (after i did a 12 hour stint with no food. Found any long life packets that only needed boiling water invaluable.)
Crocs for the patient!!!! Everyone needs crocs in hospital! Ones with a moveable back strap so they can slip on/off around the ward but still provide a bit of support for a lazy walk. More useful than flip flops because you can wear them with or without socks/Support stockings. And you can bet you forget shoes for the patent in an emergency if their wheeled onto an ambulance
Fluffy socks/slipper socks for carer
Lightweight smartish long cardigan for me
The old fashioned tins of Nivea moisturiser
A cup with a lid for me. Found this was better than it bottle of water, lighter to carry. I could fill it with either water or coffee and i was less worried about spilling hot water.
Had a couple of different cheapass brightly coloured hanging wash kits like this https://amzn.eu/d/01RSepOR
one was the wash bag. the other had everything like pens, chargers, playing cards, food packs, squash. It meant I unrolled/hung up stuff quickly at admission, and I could find stuff easily in my bag or at the bed.
Also the hospital holdall was a stupid bright colour/pattern so I could say "grab the bright ___ holdall" and Noone could mistake it.