Spyro, Magnus and Ignitus are from Activision's Spyro, Valoo's from Nintendo's Legend of Zelda: Wind Waker and this screenshot's taken from Valve's Garry's Mod.
Inspiration: The dragon dudes' singing part of This Island Belong To Us from Walt Disney's Sofia the First. https://www.youtube.com/watch?v=mN6FEKslvbU

These dragon dudes prepared themselves to perform the most handsome and giant-bellied performance they've ever plan to tried by building up the fiery breaths in their bellies, enough to make them huge, and begin their fun and playful song for you guys. Enjoy.