Here a picture with a lot of Ponies from the newer seasons while they sing together. The base was this screenshot. I worked three weeks on it (with breaks where I made other vectors). The background is selfmade.
 
Ponies from left to right  
First row: Coco Pommel, Moon Dancer, Coloratura, Sugar Belle, Tree Hugger & Vapor Trail  
Second Row: Cayenne, Citrus Blush, Lily Love, Pretzel, North Point & Sweet Biscuit  
Third Row: Mare E. Belle, Mare E. Lynn, Pearmain Worcester, Pegasus Olsen, Moonlight Raven & Sunshine Smiles  
Fourth Row: Clear Skies, Sunshower, Dear Darling, Swoon Song, Fond Feather & Silver Berry