One day, back during my college years at a friend's house, I had the grand idea of trying to write down every game I had beaten. It ended up being a large brainstorming session trying to get the initial list formed, and since then I've been adding to the end whenever I complete something. That's why the beginning of the list is in alphabetical order; when I was finished initially, the document file I was keeping (games.doc) I sorted. Since then I've kept any new additions in the order I've beaten them, which has been a nice look back and see the patterns in what I've been playing.
6/24/20: A GIANT WORK IN PROGRESS! Adding everything will take awhile and I've always wanted to write a little about each game (years ago I was doing this on Twitter for new additions), so everything might be kind of slapdash for some time.