OpenGameArt.org
Heartfelt Battle (Loopable, fantasy, strings/piano/horn)
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"Heartfelt Battle (Loopable, fantasy, strings/piano/horn)" by request licensed CC0: https://opengameart.org/content/heartfelt-battle-loopable-fantasy-stringspianohorn
Where to put it: Game credits or video description. If the entry has a "Copyright/Attribution Notice", follow that.