I usually just bookmark games and move the ones I especially enjoy to a different bookmark folder I check every now and again
If you want to be a real hero however you could simply write a review for every game you try and keep track of them that way. Probably the role-model approach, if it wasn't for some asshole that thought inventing laziness was a good idea. Well, it is what it is. I bookmark.
Bro don't you remember the games you has played with saw the images in the download profile? I ever remember of that way because never remember the names.
I save copies on an external. Thinking about doing a spreadsheet at some point. I don't keep the ones I didn't like and quit, but I'm unlikely to forget those.