The Magic of Chaos (5E)

From publisher blurb: The Magic Of Chaos introduces a new way of adding spell-casting monsters to your campaign. The threat of Orcus, and Chaos in general, is a looming presence in the land of Cairnvarthi. Make your players feel its glorious, evil power with monsters that attack with a bang! Included in this small tome are twenty new spells for shaman monsters, almost all of them scalable to be used by anything from the lowliest goblin shaman, up to Orcus himself!