Why don’t you pay attention to all the stuff you do in a normal month to make your own list? I think we tend to take for granted all the little stuff we do all the time, so it’s easy to forget what we used to not know.
E.g., feeding yourself: that’s not just basic cooking, but how to plan a menu around what you have and what’s cheapest and make a balanced meal, making a list, how to grocery shop (looking at unit prices, being aware of all the tricks like putting appealing crap on the end caps, etc.), how to read a recipe and scale up/down, etc. One thing I am doing is doing the planning and list-making with DD, and then putting the requisite amount of money on her debit card and sending her to the store - she has been shopping with me for years, so I was surprised how intimidated she was figuring out what is where on her own.
Also, taxes. What documents you need, where you find the instructions, what numbers go where, what documents you attach (if filing by mail), etc. And just forms in general - how to fill out a W-4, how to open a brokerage account, how to make a secure password and manage your passwords and other private information. How to set up a basic filing system at home to keep your documents organized, and a tickler system so you know what bills need paid when (assuming you can’t auto-pay everything of course - and how to set up auto-pay!).
How not to be a dick. E.g., drive in the right lane until you need to pass, use your turn signals, and get back after you complete the pass - and maintain your speed so you’re not pulling back in front and then slowing down. Don’t walk three abreast down the middle of the sidewalk, and move to make room for people passing from ahead and behind. Say please and thank you to waitstaff and tip generously. How to complain/speak up for yourself politely and professionally.
And finally: how to ask for help. If there is one thing my DD hates above all else, it is asking an adult for help. I need to demonstrate to her (over and over again) that even adults don’t actually know everything, and that it is entirely appropriate to ask questions when you don’t know where something is or what to do next.