From publisher blurb:
Fearsome Raiders and Stalwart Sentinels!
In many ways, frost giants and stone giants have little in common. The former are known for their love of warfare and raiding, and live primitive nomadic lives in the frozen wastes, while the latter are a reclusive and relatively peaceful race, in general, who do what they can to live quiet agrarian lives, despite their intimidating size and appearance. Though they are very different from each other, they are perhaps the two giant races that are most relatable to humanoids, and the ones that provide the most interesting and varied uses in your games.
This book presents game statistics for the mythic frost giant and mythic stone giant, both of which have unique abilities never seen elsewhere. Mythic frost giants (CR 12) can create powerful avalanches, to bury their foes, and can breathe great gales of wintry chill that leave their victims frozen solid, among other powerful abilities. Meanwhile, the mythic stone giant (CR 10) can create powerful earthquakes with the swing of a club or the stomp of a foot, and their tough, rocklike skin is incredibly difficult to pierce or otherwise harm. Beyond that, their mastery of rock throwing is unrivalled, and they have a variety of other powerful abilities to call upon as necessary.