This sound effect can be found on The General Series 6000 Sound Effects Library, which was made by Sound Ideas. It is the same track as Sound Ideas, MONSTER, FANTASY - GWYTHIANT SNARL 05.
It is the seventeenth sound in Hollywoodedge, Elephant Tiger Combo PE980903.
Links:
http://www.audiomicro.com/large-animal-roar-creature-royalty-free-stock-music-887462
https://soundideas.sourceaudio.com/track/7620197
https://soundeffects.fandom.com/wiki/Sound_Ideas,_ANIMAL,_CREATURE_-_LARGE_ANIMAL_ROAR_12#Audio_Samples
