I once saw a commercial of Equestria Girls: Rainbow Rocks where Sunset Shimmer was holding Spike. I thought that meant they were a couple. I hope they become a couple soon!!!

Spike is too young for dating others.

This is one of the few pairings that isn't totally weird or anything. It's plausible. They used to be a couple 👫 too. I just hope it happens again to shove it up to those annoying 'Flashlight' shippers.

She dated the human version of him. It wouldn't be surprising if they got back together now that she has changed her ways.

Obviously Sunny should be with Twilight Sparkle. But why? For one, Flash broke up with her. And while Sunny met up with the Dazzlings, she is in a rivalry with the three. I don't think Spike would be adequate with her. Sunny doesn't even know Trixie. And so, Twilight Sparkle and Sunset Shimmer should be together.

Adagio Dazzle of course.