@Drama King  
superman would curbstomp everyone but discord, since discord is the only one here with the powers of a god.

The best method to beat superman is to have one threaten the audience whilst another tries to take out superman when trying to save the spectators (if there is an audience that is).  
Discord could possible transform into a piece of Kryptonite right?  
Or what if the reason why the Changelings are green because they naturally emit a Kryptonite glow (I know a real stretch and WTFC).

@Keith Mowz  
Mxy likes Superman. Discord doesn’t. Even if Discord isn’t as powerful as Mxy, that makes a world of difference. If Mxy wanted to destroy Superman, he wouldn’t even have to wriggle his eyebrows.
 
Drama King seemed to be assuming a scenario fight, which would give the other characters time to plan, and mean that Superman wouldn’t go full force immediately.

I doubt Discord would stand that much of a chance. Superman’s already used to dealing with reality benders like Myxyzpytlyq (Not even going to try to figure out how its supposed to be spelled)
 
Plus going by the criteria of “going full-out from the word go”, the Death Battle of Superman Vs Goku’s extremely thorough analysis taught me that full-out Superman is a solar-system obliterating juggernaut. Everyone involved not literally made out of solid magic is dead in less than a second.

@Background Pony  
Lavan might be able to bring some muscle to bear, I don’t remember just how powerful he ended up, but the only guy I’d give good odds against Superman is Discord.
 
Trixie and Squirk might be able to transform Superman using their amulets, but I don’t think they’re fast enough to pull something on a guy with super speed and a lot of combat experience against everything from outer space wizards to aliens from the past. Most of the villains are just distractions for Discord to use to put his plans into action.
 
To be fair, Discord’s power means that Superman probably can’t take him in a direct fight, meaning that he’ll have to dip into his allies to win, assuming that Discord’s eventual plan leaves him the chance to do that.

I think Tirek, Catrina, the Witches, the bees, Porcina, that Penguin guy, Lavan, Grogar and the whole of Tambelon, Somnambula, Arabus, Nightmare Moon, Discord, Chrysalis AMD Sombre might stand a chance.

@Drama King  
Post that on CBR if you wish, but be warned, the posters examine the fighters and their abilities very closely. Feats matter, not hyperbole, and victories are not decided by plot. By default, fights take place in a Roman Coliseum kinda thing called the Khazaan Arena, and all characters are bloodlusted, fighting to their best ability to finish their opponent as quickly as possible. You’re going to want to specify that a fight is a scenario.
 
Point by point, and using the Post-Crisis Superman that I am familiar with…
 

How about this? The villains of Friendship is Magic vs. Superman.
 
I believe they could potentially beat him, and here’s how.
 

Thank you.

@Sjogre  
Did so!

Hey, would you mind putting in source links for these? Sometimes the fights on that site would go into weird tangents.
 
If nothing else, there was a Care Bears respect thread at one point, so you know that they would do their homework on a fight.