One day, Celestia and Luna, two scientists living in Ponyville, were exploring a mysterious castle where they found a strange jewel. When they took the jewel back to their laboratory to run tests on it, 15 lights shot out of it. Then three of the lights cause supernatural events and gave three normal girls superpowers.

This is not power ponies, but this is based off Powerpuff Girl Z but you don't need to watch it.

This story focuses on teenage junior high school student Rainbow Dash and her classmate and crush Soarin Skies.
They team up as they transform into courageous, vivacious superheroes known as Daydream and Midnight to keep Equestria safe from the evil Chrysalis and his army of mind-controlling akuma. But they fight together not knowing the true identity of each other.

Rainbow Dash as Daydream/Ladybug

Soarin as Midnight/Chat Noir

Princess Celestia as Tikki

Princess Luna as Plagg

Pinkie Pie as Alya

Trixie as Chloe

A long time ago they were four warriors that fought off evil with the power of the elements of nature. They fought Erebus and two sacrificed their lives to save Equestria.

A thousand years later Erebus returns and has his eyes on the elements of harmony and their bearers.

So Aura, Gaea, Amphitrite and Hestia hand their powers down to the young pegasus mare Rainbow Dash and she will become Iris, spirit of the elements of nature.

But with having to deal with being the new wonderbolt, a curious alicorn close to revealing her identity, three noisy fillies almost getting killed, lying to friends, having a crush on a certain wonderbolt and being Equestria's new hero it ain't going to be easy.

Art work by Oceania Featherthorn.

Siren daughter of Sombra, Shadow Fall wants to have a normal life and explore the world. So she escapes her father's castle and becomes the awesome Rainbow Dash. Soon she and her new friends are battle villains together, including Sombra.