Hello, My Name Is, by LoyalLiar
Zero-ish spoiler summary: Right before the invasion of Canterlot is supposed to commence, a changeling suddenly finds itself completely magic-less and unable to change its form to blend in... and "laying low" is not an option.
A few thoughts: There's a lot of good comedy in this story, centering around just how oblivious people (ponies) can be; all the story's best moments revolve around how highly visible this changeling is, and how aggressively everypony fails to notice anything out of the ordinary. Also, stupid puns! I love stupid puns! But what I wasn't as happy with was the characterization of the main character himself: although his murderous, mean-spirited tone was sometimes comical, I found that more often it took the story to a darker place than I was comfortable with for what is, at its core, an absurd comedy. Joking about how much better "Limited Liability" (the pony he was replacing) got at his job after he was replaced is one thing; casually tossing out that the real LL is presumably already dead moved the tone rather farther afield than I was happy with.
Recommendation: If you don't mind your comic stories on the dark side (as distinct from dark comedy; this is fairly light comedy with some very dark trappings around it), then you'll probably find this a nicely humorous jaunt.
Fugue State, by horizon
Zero-ish spoiler summary: Lyra can't stand the musical numbers that pervade Ponyville; the ensemble songs which materialize out of nowhere and overtake everypony in range, forcing them to sing and dance and occasionally horribly injure themselves. Bon Bon doesn't see why it's such a big deal; she thinks they're kind of fun, herself.
A few thoughts: This story is weird, and I mean that in a good way. I liked the idea, and I liked that the author did more with it than "what if those songs were really happening, ha-ha, wouldn't that be something?," and instead thought a little bit about how ponies might react to that if it were a constant in Equestrian life. I'm kind of uncomfortable with how it resolves, though. I get that the emotional ending made sense, but being in a song-center like Ponyville still seems like something that regularly threatens one's very life in this vision of Equestria (we hear about several serious injuries from previous musical numbers, and Bon Bon nearly breaks her neck), and everyone just kind of seems okay with that. They could have made the decision to take that risk for the love of music or somesuch, but instead that whole issue seemed to get ignored at the end in favor of the mental/emotional angle.
Recommendation: If you're looking for a good treatment of a sorta-silly premise, this story delivers.
Ruled by Sin, by Pearple Prose
Zero-ish spoiler summary: The tale of how one dragon rose to rule his breatheren, but overreached his immense power.
A few thoughts: This is worldbuilding, through and through; there's no pretense of a standard narrative here. Instead, what you get is a fictional biography. I'm amenable to that kind of thing (biographies can be good, even great!), but this one suffers some problems. First of all, it's very symbol-laden (the titular dragon is literally named "Sin," after all), which somewhat interferes with the straight-history storytelling style. Second, the story ends very abruptly, and I found it unsatisfying in its whimper-conclusion. With that said, the worldbuilding is clearly the draw here, and that was interesting and portentous without fail.
Recommendation: While this story is only for fans of lore, it does hit that note strongly and effectively; to that specific audience, I'd suggest giving this a look.