I currently downloaded Itchio for an app bu then deleted it. It was 8 GBs and now it won't leave. I deleted Itchio but it took away 8GBs of free space. Help

I don't understand. You don't need the Itch app to download anything from Itch.io, unless you want to use it. And uninstalling the app might not delete the games you downloaded with it. Check your application data folder (App Data on Windows, probably .local on Linux). Hope this helps.