I stumbled across this picture where we have Pinkie pie, Rainbow dash, Rarity, applejack, Fluttershy, and spike with Capper marching to Next level of Canterlot.
 
now what Caught my Eye was the scene from the Trailer to “Mann vs Machine” from Team Fortress 2 Where Just Red Heavy, Scout, and Engineer and blu Solder, Demoman, and Medic Marching to face the Robots
 
and Its kind of funny How “Almost” all of the Crossover Teamworks could of worked
 
 
Pinkie Pie- Medic
 
Rainbow Dash- Scout
 
Capper- Heavy
 
Spike- Demoman
 
Rarity- Solder
 
Applejack- Engenner
 
Fluttershy- (well you all Decide)