This app was mentioned in 2 comments, with an average of 1.50 upvotes
I guess I post my own. Imo its the best one out there for EDH (I couldn't find a good one, where I don't have to change players or something)
1-6 players, Partner Commander support coming soon.
https://play.google.com/store/apps/details?id=de.mitja_henner.tcgsidekick
I wrote an Android app with a deck builder:
https://play.google.com/store/apps/details?id=de.mitja_henner.tcgsidekick
You can check the oracle text offline or fetch the card image from gatherer.