There are a few new monetization methods out there such as Kiip that you should check out, although I can't speak for how well they work.
One new monetization method that I can speak for, which is proven to work are, real-money gambling and betting mechanics, which produce monthly ARPU in the neighborhood of $300/month -- that's 300X better than the other monetization options currently available to game devs. I know the knee jerk reaction is to think you can't do that without a license and that obtaining a license is nearly impossible, both of which are true, but Betable (developers.betable.com) just launched a real-money gambling engine that hosts and operates all gambling code on behalf of a game dev, enabling them to piggy-back on Betable's licenses, so they don't have to get their own.
FULL DISCLOSURE, I'M THE FOUNDER OF BETABLE. Sorry for the self-promotions, but given the current state of game monetization methods available to devs, I thought it was important for me to jump into the conversation and make people aware of what else is out there. Hope this is helpful.