...Ok. Her name is Cloud Kicker. This is fanart for one of the most amazing stories ever written.
You start your journey here. The-Incredibly-Dense-Mind-of-Rainbow-Dash [link] While not directly the story of Cloud Kicker and Blossomforth , they feature prominently, and this story sets up for the main attraction. The-Life-and-Times-of-a-Winning-Pony [link] This is the main attraction and while there are several spinofs and alt universes this is the core of the Winningverse cannon. The-Incredibly-Troubled-Mind-of-Rainbow-Dash [link] This is a side story that while not essential provides a good filler and insight into RD's mind and the status of her relationship with her marefriend. Further reading should be- The-Study-of-a-Winning-Pony By Ponibius [link] Some events and Cloud Kicker herself from Twilight's perspective. Not heavily tied to to the events of Winning Pony but heavily influenced by it. Also, The-Lesson-Plans-of-a-Winning-Teacherby Cloudhammer [link] More heavily tied to the events and of course from Cheerilee's perspective.As above a damn good if currently short read. Last I add these two Saying-Goodbye [link] Feeling-Regrets [link] Both written by the Chengar Qordath(author of most of these), this is an alt universe wherin Derpy gets sick...really sick. It seems it was a character exploration exercise and its written insanely well but it's nine kinds of sad. Read it, but its gonna hit you in the feels. Thats all of it as far as I know.
If you have the time read them all and although I would read the last two to coincide with their earlier chapter equivalents, if you aren't normally a reader you might want to make an exception.