If it can be done via RSS, then an *arr tool can be developed. Unfortunately I'm not a coder 😓
I tend to grab releases that seem interesting to me (then buy the full game if I like it), but rarely install all of them. I'm more interested in the organization of the .zip/.iso I have laying in a folder, knowing what I have and what I should snatch.
It seems like you don't need an arr like tool for your use case. ARRs are designed to download targets that meet criteria, you're looking to download everything.
Instead it sounds like you are looking for a way to browse your downloaded games on a GUI like interface to help you pick which ones to install?
Breaking from if you need or need not an ARR; is your use case a GUI that lists your downloaded games and pulls the cards from IGDB.com?