This is very interesting. With the recent confirmation that a leaked list of the titles of episodes 13-19 of season six is correct, it's beginning to look like DHX is running a leaky ships in terms of keeping the titles of the rest of the episodes of this season secret. This adds weight to the possibility that one of the two lists of episodes recently published anonymously may be correct.
I thought that I'd let my imagination run riot and consider what these episodes might be about. We don't know either of even if any of these titles after episode 19 are correct so take my predictions with a healthy dose of salt (lick):
#9 (Broadcast #13) - The Fault in Our Cutie Marks
The Cutie Mark Crusaders encounter a group called the 'Mis-Marked' who believe that they have the 'wrong' cutie marks and want Starlight Glimmer to remove them so that they can find their 'true' destinies. Can the Crusaders help these ponies to understand their Cutie Marks properly or will Starlight Glimmer have to face a dark temptation of the worst kind?
#14 - Stranger Than Fan-Fiction
Rainbow Dash is visited by A K Yearling, who is more than a little annoyed about fan-stories about Daring Do that she has been publishing in the Daring Do fan magazine 'Pith Helmet Ponies'. However, when the events in the story start being reflected in the adventurer's real life, she and Rainbow have to determine whether fiction is really coming true!
#15 - The Cart Before the Ponies
Scootaloo has her awesome stunts and Sweetie Belle has her singing, but what individual talent does Apple Bloom bring to the table? When the annual All-Equestrian Box-Cart Rally comes to Ponyville, Apple Bloom may be about to find out!
#16 - 28 Pranks Later
Applejack/Twilight Sparkle Cutie Map episode. The Cutie Map sends the Princess of Friendship and the Honest Farm Pony to a distant town where harmony has been torn asunder apparently by one of Cheese Sandwich's parties! Using a mix of time magic and Applejack's infallible instinct for deception, they must find the cause of the trouble and see who is really responsible for the troubles afflicting the town!
#17 - The Times are a Changeling
Matilda Donkey is called before the Council of Friendship to explain the Changeling lodging with her and Cranky. It is up to her to prove that even a Changeling can feel and use the Magic of Friendship.
#18 - Dungeons and Discords
Discord crashes the Game Evening at the Castle of Friendship and observes the Mane Six playing the tabletop RPG 'Caverns and Chimeras'. Considering the game 'tame', he sends the Six through the wall of the dimensions into a real sword & sorcery adventure! Including Dungeon Master!Discord!
#19 - Buck-Ball Season
Buck-Ball is Equestria's top professional sporting event and ponies can get a bit... excited about it. However, some take it a bit too far and, when team loyalties threaten the unity of Fillydelphia, The Cutie Map calls Fluttershy and Rainbow Dash to help remind the people of the city of the things that unite them.
4Chan Episode List
#20 - Pet Peeves
Mane Six pets vehicle. Whilst the Mane Six are away attending the Court of the Two Princesses, Starlight Glimmer is tasked with caring for Owlicious, Opal, Tank, Angel, Gummy and Winoa. I mean, she's the most powerful Unicorn of her generation! A sextet of pets can't challenger her, can it?
#21 - Where No Pony Has Gone Before
Above the realm of the pegasi lies the void separating Equestria from Luna's Moon. Can this be crossed without magic? Rainbow Dash, the greatest flier of her generation, is tasked to be the pilot of the first attempt to find out!
New Secondary Character - Whinny von Braun, Rocket designer pony extraordinaire with a shady past in the Sombra regime in the Crystal Empire.
#22 - Caving In
When the Diamond Dogs start having problems with another clan they ask the most persuasive and frightening pony they know to help them - Rarity! The question is whether she is quite cut out for the cut and thrust of Diamond Dog diplomacy!
#23 - Frights, Camera, Action!
Trixie appeals to her new best friend Starlight Glimmer for help when she finds that her Nightmare Night-themed show isn't quite getting the response she wants. The problem is that Starlight, while powerful, has a little trouble keeping the special effects this side of terrifying. It's time for Trixie to teach her friend the way to entertain with a scare!
#24 - Spell It Out
Just who is the more powerful mage? Twilight Sparkle and Starlight Glimmer intend to find out and Ponyville (and reality) may never be quite the same again!
#25 & # 26 - The Flurry Heart of the Swarm
At the request of Sunburst, the Mane Six visit the Crystal Empire to find that everything is... odd. Sunburst has inexplicably been dismissed as Flurry Heart's tutor in magic and everypony is a bit reminiscent of Equalist Cultists. Cadance avoids her sister-in-law for a while and soon the truth comes out: Chrysalis has invaded again, hoping to turn the pure love of the alicorn baby Flurry Heart into an inexhaustible power battery for her magic and for her swarm.
There follows a very action-oriented episode with the Mane Six fighting in a situation when they can't be sure who is a friend and who is a foe. It climaxes when Chryalis tries to use Flurry as a Love Magic bomb only for the little alicorn to somehow seize control of the newest Changelings, grown in the Crystal Empire in a sea of love magic from the little alicorn and the Crystal Heart.
Right at the end, Chrysalis flees along with her few remaining followers; the Changelings then come to do obeisance to their new infant Queen - Flurry Heart.
#20 - Viva Las Pegasus
It's vacation time for the Mane Six! At Rainbow Dash's insistence, they try the sights and sounds of Equestria's #1 entertainment city. However, they very quickly find themselves hoping that what happens in Las Pegasus stays in Las Pegasus!
#21 - Every Little Things She Does
Trixie star vehicle; Starlight Glimmer tells the story of The Humble and Penitent Trixie's Equestrian Apology Tour to explain to Twilight Sparkle why the Mistress of Illusion Magic is the best friend that she could have ever hoped to have had!
#22 - PPOV
Pony's Point of View; probably stylistically similar to Slice of Life. One of the Background Ponies tells the story of a day in the life of Ponyville, the friendliest and most normal (hah!) towns in Equestria.
#23 - Where the Apple Lies
Applejack is the most honest pony in Equestria, isn't she? When Babs Seed and her parents visit Sweet Apple Acres visit from distant Manehattan, Applejack is forced to admit to the one time that she truely betrayed the trust of everypony she loves.
#24 - Top Bolt
Rainbow Dash the Wonderbolt adventure; Now she's in the main team, Rainbow Dash is invited to the annual Top Bolt aerobatic proficiency exercise at Fort Whinnimar AFB, at the northern edge of the Great Badlands. Amongst the most challenging flying conditions in Equestria, she is up against her team mates and several ponies from outside the team to determine who is the best flier of them all!
#25 & # 26 - To Where and Back Again
Princess Ember summons Spike (and, through him, the Mane Six) to the Dragon Lands. Her father has brought her news that the oldest and most powerful of the dragons (her great-grandmother) has awoken from a thousand-year-old sleep and is threatening to soar forth and devastate the world to sate her never-ending lust for gold and jewels for her hoard. The Mane Six must set out on a quest deep into the unexplored Dragon Lands to confront this ancient Dragoness and stop her... if they can.
After a long journey encountering several odd creatures and occasionally having to fight off Garble and his thuggish allies, the Mane Six must confront the ancient Dragon Lady Tiamat. Will Ember be able to demand her great-grandmother's obedience through the magic of the Dragon Lord or will the Mane Six have no option but to use the Rainbow Power to end this threat forever?
Okay, that's my ideas! What do you think?