If I were to design a magical smartphone, these are the apps I would include. The phone would be able to shoot fire and lightening. I would have apps to turn me invisible and to conjure weapons. The phone would also be able to summon creatures from other dimensions or plains of existence. It would enable me to teleport and interdimensionally  travel. I would basically include an app for as many spells that I could think of that are present in D&D, Skyrim, Magic The Gathering, and so-forth.