It's rarity and fancy pants's Chilldren XD

Base-
https://www.deviantart.com/raini-bases/art/MLP-Base-8-489034809

DeviantArt-
https://www.deviantart.com/beikiart/art/MLP-Next-Gen-Hello-774699560?ga_submit_new=10%3A1543565032

Reference image-
https://www.youtube.com/watch?v=xA2OkJNiSFQ

Song
1. Generosity Aftermath Remix