This is all still a rumor, but apparently, people who went to the London Toy Fair 2015 were given an exclusive look at Hasbro's upcoming toyline, and were given a guidebook with info about the toys.
According to the people who are talking about the guidebook (scans are still forthcoming), this August, we will be treated to the third Equestria Girls movie. In this movie, the Wondercolts go up against the Shadowcolts in various sports games.
Now, if that sounds lame, keep in mind how bad the synopsis of Equestria Girls 1 was. "Sunset Shimmer steals Twilight's princess crown and flees to another world. Twilight must pursue her to get the crown back, while surviving high school!"
Also, I'm totally betting that Twilight's human counterpart is a Shadowcolt.
Now, I wouldn't post something like this without SOME proof, so here's a bunch of images of the toys with the "Friendship Games" branding on them: