The Round Stable

With the show now over, I thought I'd go over how many episodes each character appeared in. This list courtesy of the MLP Wikia

For this purposes, I'm only including episodes where they have at least one speaking line. I'm not counting episodes where they appear with no lines, whether in the background or in the focus shot.

I'm also only counting regular episodes, so no movie or TV specials or shorts for this list.

With that out of the way, out of 221 episodes...

Twilight Sparkle: 181
Applejack: 164
Rainbow Dash: 160
Pinkie Pie: 156
Rarity: 149
Fluttershy: 145
Spike: 139
Apple Bloom: 63
Princess Celestia: 52 (in the first episode she only speaks via off-screen narration)
Scootaloo: 50
Sweetie Belle: 50
Starlight Gimmer: 43
Big Macintosh: 39
Granny Smith: 36
Princess Luna: 29
Discord: 23 (24 if you count Grogar's appearance in "Frenemies")
Smolder: 20
Ocellus: 18
Gallus: 17
Zecora: 17
Yona: 16
Silverstream: 15
Trixie: 14
Sandbar: 14
Derpy Hooves/Muffins: 3

Some notes:
None of the characters appeared in every single episode. However, Twilight appeared in every Season 1 episode, and Applejack appeared in every Season 3 episode.

By Season 5 there were fewer and fewer episodes where all of the Mane 6 appear together, so it became common for characters to not appear for several episodes in a row. Fluttershy in particular suffered from this, to the point that Spike appeared in more episodes than her that season (Spike was in 16 episodes, while Fluttershy was in 14).

Starting Season 6 we started getting episodes where none of the Mane 6 appears. Episodes where they never appear are:
"On Your Marks" (focuses on the CMCs)
"Hard To Say Anything" (CMCs and Big Mac)
"To Change a Changeling" (Starlight, Trixie, and Thorax)
"Marks and Recreation" (CMCs)
"The Break Up Breakdown" (Big Mac, Spike, Discord, and the CMCs)
"Frenemies" (the villain episode. Although Chrysalis turn into Twilight briefly just to mock her)
"Student Counsel" (Starlight and Trixie)

Applejack and Fluttershy appear in "The Big Mac Question", but none of them speak.

Technically "Frenemies" is the only episode where no Season 1 character appear. The only Season 1-era character to appear in "To Change a Changeling" and "Student Counsel" is Trixie.

Zecora had no speaking roles in Season 6, although she made silent cameos in two episodes.

Man Dash is gonna be pissed she's not in first place

Neat how often Applejack appears in total, while still being a character that got surprisingly little focus and development at times (and was considered a "background pony" by fans)

The main thing about Applejack in that regard is that she's the only one of the main characters who started the show without an arc. She had already arrived at where she wanted to be in life, and while her upfront and honest nature occasionally made her do or say the wrong thing, it was never something she really had to work on. Basically her entire purpose on the show could be summed up with



She was the grounding presence and voice of reason to the rest of the group, and the role suited her just fine, IMO.

Oh, it's a role I adore. I think we need more characters in stories who show that being the backbone isn't a bad role to be. It just meant she was a bit tough to write for some of the show's contributors and as a result I think she became a bit too much of the "Mane 6 pony we can insert everywhere without really giving her purpose". AJ is my fave still, so it's not some huge problem, but I would have loved a bit more substance for her sometimes.

I am legitimately shocked that Twilight didn't appear in 40 episodes.

Here are the number of episodes the Student Six appeared in.

Smolder: 20
Ocellus: 18
Gallus: 17
Yona: 16
Silverstream: 15
Sandbar: 14

Given that they only appeared in the final 2 seasons, they appeared in a decent amount of episodes. Smolder had the most appearances, while Sandbar has the least.

Gallus is the only one of the bunch to have a dialogue in the final episode.

Realized I forgot to add Big Mac and Granny Smith to the list, so they're added.

Big Macintosh: 39
Granny Smith: 36