Mighty Battles is a game I'll recommend. It's a strategy base game that's 100% PvP.
What's some other ones out there?
I'm having a grand old time in Goddess Primal Chaos. Lots of kill for DPS, tank, ranged.
I also play Disney Magic Kingdoms and Pearls Peril
Avoid the newest Futurama game. MONEY DRAIN!!!
The Patricians if you can find it.
Westward IV. Tradewinds Legends (1 or 2).
Hero and Sass: Don't think those are mobi formatted, yet. I'll throw in Boom Beach because I think it has been.
Castle crush a nice pvp game
Plants vs. Zombies.