In my achievement showcase there is an item which says that I have 1 perfect game (which means 100% of the achievements gathered). So I browsed my games game by game and was still unable to find that specific game. There is also no link in the showcase. After some googling I still have not found a way to find the perfect games in Steam.
So, where can I see my perfect games in Steam?
Steam does not provide such functionality. You need to use a 3rd party tool. One of such websites is AStats.
Once you’ve found your profile, you’ll be able to navigate to the page with games completed 100% like in this screenshot.