Like many above, Heroes 3 from time to time, something from Legacy of Kain (I have SR2 installed right now). Today I've started up Atari emulator π
Also, a lot depends on what do you mean by saying OLD. I've started playing Assassin's Creed titles last year ... I mean from the very first title, which was 10 year old already.
Or again, last year I've started playing Hitmanβ’ (form 2016, as of now, still last tile, only for 3 more days π ). That was the very first Hitman for me. After that I've played Absolution (2nd to last game) then I;ve tried moving to the very first - Codename 47. Yes, I've completed 3 or 4 missions, but after I've closed the game, I couldn't force myself to return ... it waits on my drive π
So yes, I am playing old games most of the time depending on the definition of "old" one would use.