Talk:List of episodes/@comment-3410511-20171027012124/@comment-5837525-20171027160045

Season 4 dealt with the Chest of Harmony.

Season 6 didn't really have a "theme" at all ("Explore Equestria" was a big marketing push at the time, but there wasn't much "exploring" to be had.)

And season 7 didn't introduce the Legends into halfway into the season.