@Darth Sonic  
im pretty neutral to him as a character, i just sometimes find it fun to laugh at his design. at the very least i like him more as a villain than chrysalis even tho she is higher

@Nightmare Fuel  
Come on man, show Sombra a bit of respect! He’s been around for half a decade by now!

discord preredemption > starlight preredemption > tirek > nightmare moon > chrysalis > some evil oc >>>>>>>>>>>>>> shit >>>>>>>>>>> worst ponies

Discord or Starlight…. although do either of them really count????

Chrysalis  
She managed to conquer Equestria twice
 
Most wasted potential?  
Discord and Starlight, who should’ve had much longer redemption arcs and character focus  
Nightmare Moon should’ve stuck around in Luna’s mind and tormented her instead of the Tantabus
 
Everyone else was pretty much one-and-done

1.Flim and Flam  
2.Discord  
3.Lord Tirek  
4.Queen Chrysalis  
5.King Sombra  
6.Nightmare Moon

@Embracethechaos  
One minus character and out of this fandom you go.
 
Reminds me of the Twilicorn Drama thing.

@Background Pony #4D33  
same. Without Discord, I wouldn’t even touch mlp. But because of him I’m addicted to it. If the writers don’t make him awesome in season 6, I’m outta this fandom

@Background Pony #CB64  
The thing is, Chrysalis and NMM had already Celestia out of the picture, while Sombra didn’t have the chance. Still, the war was going well for his side. We all know Discord and Tirek are overpowered. But what I love the most are villains who use law for their bad deeds, and the Flim Flam brothers most likely bought those lands.

All of them putting Sombra and Starlight aside were able to conquer Equestria in their timeline. Sombra confirmed as a lesser evil than the Flim-Flam bros.

@monikerpending
 
And/or was misguided.

@Goobington  
A true villian can never reform. Any individual who claims to be a villian but reforms, was only being obstinate and crying for attention.

@Goobington
 
Not bad. You’ve earned a Brent Rambo.
 

Discord

I’d say Discord but I’d likely get flooded in hate.  
There isn’t any other reason I’m in the show to be honest,  
Didn’t even catch up on the episodes after the last Discord episode aired.

Still waiting for him  

Starlight, followed by Chrysalis, followed by Tirek.
 
Chrysalis was my favourite villain before, because there’s interesting subtext about how she’s fundamentally doing what she does out of duty towards her subjects, which makes her a foil to Celestia. Or how she views love as a resource rather than an emotion, which makes her a foil to Cadence. But Chrysalis is interesting because of the other characters around her.
 
But I really have to give it to Starlight. This is because she’s frighteningly competent, real, and culturally relevant.
 
First of all, her competence. She’s an exceptionally powerful unicorn; able to match Twilight in terms of magic, and able to personalize spells so that only she can control them. She’s also an excellent planner, spending the entire season putting her plan into motion, and being two steps ahead of Twilight. She’s also a devious manipulator, able to form her own cult.
 
Unlike the other villains, there was no magical MacGuffin to defeat her. Twilight couldn’t use her status, her friends or her magic to stop her. She had to rely on diplomacy.
 
Secondly, there’s how real she was as a villain. Most villains in the show have exaggerated or fantastical goals. Starlight Glimmer brainwashed other ponies and formed a cult. That’s a thing actual people do. Her methods were also unsettlingly realistic.
 
But competence and realism only go so far. What I think propels her into ‘best villain’ territory is that her story is a form of social commentary.
 
When The Cutie Map first aired, a lot of people compared Starlight Glimmer to a social justice warrior, because of the parallels between her actions and tumblr-esque actions. This was met with opposition, with people stating that her behaviour was more akin to that of a marxist dictator. But in light of the finale, I think the parallels are undeniable. Starlight Glimmer’s entire character motivation is creating and maintaining a “safe space” (the village) so that she doesn’t have to deal with the differences created by cutie marks. Just like the Staff of Sameness, her “ideology” is just something she made up to create a sense of authenticity for her community.
 
It’s fitting, then, that when she reveals her backstory to Twilight, Twilight’s reaction is that Starlight’s motivation is ridiculous. The lesson she learns is that rather than trying to hide from the differences, she should take ownership of her life, and work through her problems.
 
(Just as an aside. So many people seem to forget that she wasn’t actually aware of the terrible alternate futures she was creating until she saw the Ashlands Timeline, and should be judged accordingly.)
 
Now, with that being said, if you dislike, or just plain disagree with the whole “SJW subtext” deal, and instead found her backstory to be kind of weak, then I can completely understand that. Before I made the connection, I found it rather weak, too. And it can also somewhat deflates her intimidation factor from the premier.
 
But even then, she still has the competence to match Twilight, play-by-play. Without the extra subtext, I’d put her just below Chrissy.

Let’s recap history of the villains who where defeated on the show and movie  
Nightmare Moon defeated by the Mane Six  
Discord turned good by the Mane Six  
Queen Chrysalis Defeated by Princess Cadence and Shining Armor  
King Sombra killed by Cadence and the Crystal Heart  
Sunset Shimmer also turned good by Twilight Sparkle and her Friends  
Lord Tirek defeated by the Mane Six Rainbow Powered  
Dazzlings beaten by the Mane Six and a little help with Sunset Shimmer  
Flim and Flam Unknown only saw them escaped in Season 4  
Starlight Glimmer turned good from Princess Twilight Friendship  
Human Twilight Turned Good from Shimmer

My favorite is and always will be Starlight Glimmer.

I’ve always had a soft spot for Nightmare Moon, and Sombra’s bad future was frickin’ epic. But ultimately I’ve gotta go with the Super Flim Flam Bros. Anypony who tries to bring industry and technology to Equestria is aces in my book.

Adagio obviously. She had the whole school in the palm of her hand and she would have won if Sunset Shimmer hadn’t helped Twilight Sparkle.

Starlight Glimmer such a good villain she had to ride the coattails of Starswirl’s spell and all the other villains.

Number one: Tirek. Imposing, to the point, dreaded and pwerfull. He doesnt need a tragic past or anything and someone who can make even Discord rethink path is someone to not be messed with.  
Number two: Before reforming, Discord. Manipulator, unpredictable and giving a good laugh. But having a child personality while having power over almost anything makes him a big treath.  
Number three: The Dazzlings (Sonata dusk is my fave but as villains they work superb as a trio). Is not just the hatred power feeling..is the charming songs and personalities what earned them a spot.  
Number four: King Sombra. Lack of screentime made up with his background, but the bad future showed that he could be one of the most ruthless and evil hearted villains. He had to be stopped before he could go too far.
 
SUnset shimmer however was the least impressive of villains but as a character i like her more than as a villain. Nightmare moon, Chrysalis and glimmer…no possition defined.
 
And the FLim Flam brothers while not having a seat, are the best snake oil sellers to be known….and with damn catchy songs as well.