All Bottled Up, the second episode of Season Seven was originally aired on April 15, 2017.

In this episode, Starlight Glimmer and Trixie accidentally make the Cutie Map disappear while the Mane Six are on a friendship retreat, so Starlight uses a spell to bottle up her anger until the map is retrieved.

It also features the song, Best Friends Until the End of Time, which is the first song of season seven.

A Canterlot Wedding - Part 1, the twenty fifth episode of Season Two was originally aired on April 21, 2012.

In this episode, Twilight Sparkle grapples with her conflicted feelings when she finds out her brother, Shining Armor, is marrying Princess Celestia's niece, Princess Cadance. Twilight also begins to suspect that Cadance has changed since their childhood.

It also features the song, B.B.B.F.F..

Owl's Well That Ends Well, the twenty fourth episode of Season One was originally aired on April 22, 2011.

In this episode, Twilight Sparkle befriends an owl who becomes her second personal assistant, to the displeasure of Spike.

Trade Ya!, the twenty second episode of Season Four was originally aired on April 19, 2014.

In this episode, friendships are tested when a trip to the Rainbow Falls Traders Exchange goes wrong.

Trivia

Tanks For The Memories, the fifth episode of Season Five was originally aired on April 25, 2015.

In this episode, to prevent her pet tortoise Tank from going into hibernation, Rainbow Dash tries to stop winter from coming to Ponyville.

It also features the song, I’ll Fly, which marks Rainbow Dash’s first solo in the series.

On Your Marks, the fourth episode of Season Six was originally aired on April 9, 2016.

In this episode, the Cutie Mark Crusaders struggle with the question of what's next after receiving their cutie marks.

It also features the song, Out On My Own, which is the first song of season six and marks Apple Bloom's first solo in the series.

Party of One, the twenty fifth episode of Season One was originally aired on April 29, 2011.

In this episode, Pinkie Pie investigates her friends’ excuses for not attending one of her parties.

It also features a song, Pinkie Pie's Singing Telegram, in which Pinkie Pie sings it to Twilight Sparkle, Rarity, Applejack, Rainbow Dash, and Fluttershy as a way of inviting them to her pet alligator Gummy's first birthday party.

A Canterlot Wedding - Part 2, the twenty sixth episode of Season Two was originally aired on April 21, 2012.

In this episode, Shining Armor and Princess Cadance are set to be married, but Queen Chrysalis has a devious plan to ruin Shining Armor's happily ever after and the future of Equestria.

The Cutie Mark Chronicles, the twenty third episode of Season One was originally aired on April 15, 2011.

In this episode, the Cutie Mark Crusaders learn how each of the Mane Six acquired their cutie marks.

It also features a song, So Many Wonders, which is sung by Fluttershy when a large swarm of butterflies cushion her fall from Cloudsdale, and she experiences life on the ground for the first time.

Castle Sweet Castle, the third episode of Season Five was originally aired on April 11, 2015.

In this episode, Princess Twilight's friends try to make it feel more like home after finding out she's been avoiding her castle.

It also features a song, Make This Castle A Home.

Sparkle’s Seven, the fourth episode of Season Nine was originally aired on April 20, 2019.

In this episode, Twilight Sparkle and Shining Armor pit their wits against each other to settle a long-standing sibling rivalry, but they soon discover they are not the only competitors.

Equestria Games, the sixth episode of Season Four was originally aired on May 3, 2014.

In this episode, Spike's nerves get the better of him when he is put in charge of lighting the Equestria Games torch.

It also features the song, Cloudsdale's Anthem, sung by a nervous Spike.