I just did a search for 'itch.io' on Google Play and found four apps called itch.io Companion, itch.io - Companion (same developer), itch.io Insights and itch.io Dashboard. I haven't installed any of them, so I don't know whether they're any good.

My comments on the Android apps were based on reviews. Actually, the mobile web site isn't too bad, so maybe we don't need a mobile app. There are some things that you can't do on the web site that you can do with the desktop app, most notably, the ability to download an html app (this is quite handy) and the ability to keep an index of downloaded apps that can be updated automatically.