Skills you may have acquired as you progressed through life that have little use at this time.

...how to kill a chicken, pluck it, take the insides out of it, and cut it into pieces before I fry it.

...balance a checkbook to the penny

That last one really irks me. I will say, though, that many people I know never balanced their checkbooks even 30 years ago.

A few that I will add include,
Using a mechanical pencil.
Using a calculator, not on the smart phone.
Using a pen and paper, writing notes on a paper calendar, writing and mailing a greeting card, writing on post-it notes.