OpenGameArt.org
RNG Experimental Volume 1
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"RNG Experimental Volume 1" by Tsorthan Grove licensed CC-BY 4.0: https://opengameart.org/content/rng-experimental-volume-1 Author's attribution notice: RNG Experimental Volume 1 by Tsorthan Grove - CC BY 4.0 - https://opengameart.org/content/rng-experimental-volume-1
Where to put it: Game credits or video description. If the entry has a "Copyright/Attribution Notice", follow that.