Sunny Starscout in A New Generation. I loved her dynamic optimistic energy. And how much of a dreamer she was.
And how much she sacrificed for her beliefs by being ostracized.
I think in Tell Your Tale she is wasted potential. I wish she were more of the beacon of hope and the initiator of things like she was in the first movie.
Part of why I like her is because of my own headcanons of her. I think she is the heart of the group and without her everyone would fall away.
For me, forget Zipp or Izzy, Sunny is my best pony. The hope of a new generation.