Tried two more games and added them to the OP.
Red Dead Redemption
A special game for me. I spent way too much time in its single player mode and then even more time in its online mode. There are still people playing it today. The first free roam I entered had a handful of players in it. I shot some of them, then tried the quick match option. I rather quickly got into a game of hold your own which was quite full at the beginning, then filled up even more. It was quite nice to experience this game again. It hasn't aged bad at all to my eyes. The next couple of matches weren't so full, though. In the end I was in a four versus two of grab the bag, which seemed kind of unfair. It's still a ton of fun, though there are, obviously, quite a lot of highly skilled players who have trained their auto-aim headshots almost to perfection.
Wipeout HD Fury
Nothing to see here. The online option only leads to a network connection error. I guess the servers have been shut down.