I did post upthread and I don't want to come across as miserable. But I have been in lockdown (and still am really) during winter.
Apart from all the practical things that would probably be a good idea to think about, we are finding mental health a very very worrying thing. I do not know if this is the same everywhere, but its a very noticeable problem.
Added to that we don't really have the financial backing from the government that those in Europe do, people are losing jobs, going hungry etc etc.
So if I had more warning, I would start donating to food banks, clothing banks, blankets for housing shelters and animal shelters. I would keep much more close eye on single friends, older people and those just going through a tough time. I know this isn't a summer / winter thing really, but I think it is worse during the winter as people are not as out and about as much.
For a personal practical side, we have very big shortages (I did mention some) of gas, vitamins especially zinc which is nearly impossible to find. Humidifiers and air purifiers are selling out as soon as stock arrives. The oils that go into those (esp eucalyptus oil) are hard to find as well.
Food stuffs have not been that much of a problem, during the highest level of lockdown, bread flour and yeast was quite hard to find, now not a problem. For us, pineapples have been scarce, but that is because we have an alcohol ban and folks have resorted to making their own.
I have not even thought ahead to Christmas, as to be absolutely truthful right now I am just operating on a day to day basis.
I mention the mental health as it is a very big issue in my household at the moment (so I may be coming in with a biased view) and it has most definitely been exasperated by the pandemic.