My top 3 episodes from each season:
Season 1: Party of One, The Best Night Ever, The Cutie Mark Chronicles
Season 2: A Friend in Deed, Hurricane Fluttershy, Sweet and Elite
Season 3: Apple Family Reunion, Too Many Pinkie Pies, Magical Mystery Cure
Season 4: Pinkie Pride, Pinkie Apple Pie, Maud Pie
Season 5: Amending Fences, Slice of Life, Crusaders of the Lost Mark
Season 6: The Saddle Row Review, Spice Up Your Life, Dungeons and Discords
Season 7: The Perfect Pear, Secrets and Pies, A Health of Information
Season 8: The Mean 6, Yakity-Sax, Sounds of Silence
Season 9: The Last Problem, The Last Laugh, Sparkle's Seven