Original description:
 
What’s a generic aviremigian that can neither fly nor has a crest? Probably a flightless deinonychosaur, which is why I chose them to represent earth ponies in the original My Little Maniraptor. They can either be troodonts or dromaeosaurids. Pinkie Pie I chose to be a troodont so she can have long springy legs for bouncing along merrily.
 
Normally maniraptor!Pinkie has fluffy wing and tail feathers like most modern flightless birds, but when she is depressed they straighten out into neat, closed-vaned feathers. I’d question how that even works, but it is Pinkie Pie.