Depends on your computing platform.
I see another reply has already covered Linux.
On a Mac, press and hold a character key and a list of accent characters will appear. There are also dead key combinations using the option key to enter special characters directly.
I have an X220 with an i5-2520M, I don’t use it for gaming but I have briefly played Half-Life 2 with it and it was comfortably playable.
So I would say mid-2000s titles and before will be fine. It really depends on the age the Thinkpad you want is, and the age of the games you want to play.