All of the Mane Six except for Twilight had alternate timeline counterparts. I feel like this was wasted potential and it could have been pretty interesting for Twilight to meet an alternate timeline version of herself. What do you think?

They were presumably all in Canterlot.

Unicorns working in dreary jobs in the capital, daydreaming about what their lives might have been, if only they'd passed that entrance test for Princess Celestia's School for Gifted Unicorns.

4893315 I agree with VitalSpark.

Lets see:
In the Crystal War Timeline: She went with Shining Armor and Cadance (who aren't married yet they're engaged and planning on marriage but the with all these catastrophes it just hasn't seemed 'right' yet) to the crystal empire but failed to stop Sombra they've all been captured and are being held captive. He's either planning on using them as bargaining chips if he needs to end the war on treaty or corrupting them and marrying(?)Cadance and turning Twilight and Shining into his Court DarkMage and Royal Darknight or something. They are not enjoying there imprisonment...

In the Chrysalis Resistance Timeline Twilight was captured in the Canterlot invasion

In the Nightmare Takeover Timeline she was close to he canon counterpart studied as best she could but without Celestia's tutoring she went of on tangents slowing her down and didn't have that royal access limiting her. She still found out about Nightmare but didn't have the courage to speak to Celestia about it/the confidence to believe it. She went to Ponyville because that's where Celestia was suppose to show up and stil tried to stop Nightmare but without he friends having moved to Ponyville in the firstplace she ended up going alone, making it to the castle despite the odds she found the elements cough*rocks* and attempted to confront Nightmare who was amused/annoyed and alittle impressed that someone had found so many key facts and offered to let Twilight to be the first to serve under her. She was offended when Twilight rejected...

Tirek eventually kills everyone and moves on...

Discord takes special interest in annoying her, which has good and bad points. She never ends up in too much danger but he always visits her and some of the things he's done...

Flim & Flam Inc. Is always looking for intelligent employees and considering they're the most wealthy company in the world its good to be a well regarded employee in there company, especially since there somewhat tribalist hiring and promoting practices work in her favor.

She's actually alive in the Barren Wasteland. She's actually among those pony's being sheltered by the team up of Nightmare Moon and Celestia on the moon. There's a mixed tribe of ponies tunneled underneath one of the mountains west of fillydelphia, and a large mixed group of survivors being sheltered in the barren wastes by what's left of a changeling hive and there doing surprisingly well. The Gryphons are largely dead and scattered, the Minotaurs got the best of a bad deal save for, the Zebras who where far enough away to remain largely unscathed their scattered tribes united to send relive efforts and let survivors know there boarders are open and willing to shelter any who make there way there.