If you're looking for a free version of Magic, there is Forge. It's a FOSS engine for MTG with multiple game modes, including an adventure mode which is extremely reminiscent of the old Microprose Shandalar game. It will even automatically download the real card art as you come across it in game.

It's under constant development with the latest cards and has multiple updates per week. I primarily play adventure and in the six months or so that I've been playing, there have been huge content additions such as quests, boss dungeons, new enemies, graphics etc

Just be warned that it is dangerous to your free time to have this available on your phone at will.