This app was mentioned in 4 comments, with an average of 1.50 upvotes
Wish granted. You need to register to download though. Also the store page is removed for some reason or other.
There's one that's just Triple Triad IIRC - but like the pokemon card app, it's only playable on a tablet.
desktop link - it's not the portal one, standalone app on its own.
For Triple Triad, seems this game is the most popular, but it doesn't look too appealing. https://play.google.com/store/apps/details?id=com.Arpian3D.TripleTriadBeta&hl=en
For Gwent, all I can find is just deck builder/helper app.