What are some useful skills or hobbies that anyone can learn for free?

I’ve been practicing this. In 30 years when computer input is primarily voice and touchscreens, we’ll be the only ones left. It’ll be like knowing how to use Morse code with a wireless telegraph.

Fun fact: My left hand is on gamer pose wasd for typing (not to f position). Doesn't really hinder me from speedy touch typing.