SecondLife is the anomaly in this list. It’s not really a game, it more a social world.
I first came into SecondLife in 2003, shortly after it started. There wasn’t too much going on at that time because people were still trying to discover what they could do. I got bored with it and left for a while.
I came back in 2008 and created Sarkany Munz. I was amazed at how much it had grown and developed. People were building things and strong communities had developed. I soon found the Tinies of Raglan Shire. Tinies are small (around 4′ tall) cartoonish animals that are powered by waffles and silliness.
I have many avatars I wear in-world, but I have the most fun in one of my Tinies and spend most of my time that way.