Chess
1
I was a semi-professional chess player back when I was younger, till my 20s, having a rating around 2200, in case you know what this is (if not, does not matter anyway!).
From then on I paused because... life, and I had to make a living etc.
But, hopefully, I will be back soon enjoying a chess game in the physical world, instead of the digital one.
I would be happy to explain from the basics till some more advanced thinking and techniques in chess, if you are interested!