To a lesser extent, Grogar and Surprise alongside the Friendship Is Magic crowd.
Fanon Discontinuity: Many fans disregard the last few episodes of the series. Not because they were particularly bad as such, but rather dropping most of the main cast to market the baby ponies. The show ends without any finality regardless, but most choose to believe the series ends with the Golden Horseshoes. Being the last multi-part adventure story, the last episode to feature the core cast of characters' it's seen as a last hurrah for the show.
Genius Bonus: In "The Great Rainbow Caper", Danny and Surprise get kidnapped by the Gizmonks, and proceed to destroy their lab from the inside. When they escape from it, they do so by getting inside a giant wooden horse. Sounds familiar?
Harsher in Hindsight: The episode "Bright Lights" features a pop star who is an homage to Michael Jackson, and his manager steals fillies' shadows as Applied Phlebotinum. Several years after the episode was produced, Michael Jackson himself began to face accusations of taking indecent liberties with children.
Tirek threatening to behead Spike, a baby, to punish Scorpan for his failure. If not then, the 'turn ponies into mindless monsters to pull his chariot' is probably the point where Tirek crossed this line.
Lavan is told that his plans for the Princess Ponies' wands might destroy all of Ponyland by throwing things into utter chaos (which is exactly what happens). He doesn't give a darn and goes ahead with his plans anyway, putting everything in danger out of his own greed. If that's not the point where he crossed the line, it's most likely when he tried to kill the Princess Ponies and their group by having them thrown into lava, primarily for spite.
Narm Charm: The cartoon's shoddy animation, amusing goofs, some silly voices, and occasional broken aesops all make the show a hilarious watch. But the D and D inspired setting, creepy villains, and some downright badass moments courtesy of the ponies makes the show awesome when it isn't silly.
One-Scene Wonder: In Mish Mash Melee, we get a personality-swapped Wind Whistler and Fizzy for a few glorious minutes.
Periphery Demographic: It's not uncommon especially after Friendship is Magic caught on to hear of male fans of this show. For many boys in the 80s and 90s, this was their first fantasy adventure cartoon.
The Scrappy: With exceptions, most fans loathe Molly and Danny. Shady can also fall into this.
Wangst: If you didn't feel that Shady's insecurities were warranted, then you saw her this way.