These are Ally's of different worlds/dimensions (which in the Sonic-verse, are called zones)

WARNING Don't get confused, these aren't forms of Ally's. To explain better, they're different versions of her from the many different zones nearby Sonic's world/Mobius Prime.

EDIT: The zone that the Ally to the far left lives in has finally been named!

I'll tell who each of them are in order from left to right

Ally of the Lunatic Zone: All of her friends died, so she now goes around killing bullies 15+ years of age
Ally of the Cryo-Zone: This Ally suffered a fatal injury and was put into suspended animation until a cure could be found for her wounds. 500 years later she was cured and released, and she found that those of her friends who weren't Lunariens lived out their full lives and died, which put her in a state of Traumna, but also did something else- made her realize how long it had been since she'd seen her friends. When she found Karono again, her knowledge of common-sense went whack, and she keeps insisting that she and Karono get married- but Karono keeps refusing because of age difference (Ally is still 15) and tells her she has no patience. But knowing that he said so only makes her more determined to get married to him. She's now the self-proclaimed maid of Karono's household, because she will do anything to please him.
Ally of the Moonlit Zone: This Ally lost her Karono in a deadly battle against Robotnik, She's child-like and cheerful on the outside, but forever hurt on the inside.
Alleena, Ally of the Shadow-us Zone: This is Ally's "Shadow". That's right kids, your shadows are all residents of the shadow-us zone!
Sara, Ally of the No-Zone: Sara is a Zone cop, she helps Zonic keep the Zones from falling apart and helps him have zones maintain stability.
Ally the Hedgehog of Mobius Prime: The Ally we all know and love. True to her speed and usage of telekinetic/wind magic, she's always around for those who need her.
Spark, Evil Ally of the Anti Zone: Evil and Badass, and Madly crushing on Scourge, she won't stop until he's hers and follows his orders to the letter. Also a fan of the Oldschool Spyro videogames.
Ally of the Discovery Zone: Nothing known about this Ally yet. she comes from the same zone as this Sonic- [link]
Ally of the Core Zone: This Ally lives in a world that was ruled by Enerjak for quite some time. She took apart her collar and stuck them to metal to enhance the quality of her powers. She's suffered many battles against friends who had their cores/souls taken away, however [SONIC UNIVERSE SPOILERS] all her friends were restored thanks to Lar -um, Jani-Ca.

All the Ally's in this picture belong to me