Frozen Caverns is a region in Niflheim, it was introduced in God of War: Ragnarök. The Frozen Caverns is one of several regions in "Eastern" Niflheim. It's connected to The Eternal Caverns and Pale Meadows, however neither of those have any collectibles. In fact, Frozen Caverns itself has only a single collectible in it, which is unlisted because you cannot return here later in the game.
Collectible[]
Frozen Caverns contains 1 Collectible Location in God of War Ragnarok. That collectible is listed down below.
Frozen Caverns - Legendary Chest-U 1[]
Contains: Runic Summon - Bitter Squirrel
This Legendary Chest is untracked, and is not required for 100% completion. This Legendary Chest is found as you explore the Frozen Caverns as Atreus, and is the only collectible in this region. At a certain point you'll drop down a ledge and see a grapple point on your right to cross a gap. Ignore it for a moment and head around the frozen pillar: up the ledge will be the Legendary Chest. The chest contains the Bitter Squirrel Runic Summon, which summons Ratatoskr's Bitter spectral form to dig up a Healthstone. Upgrades will have Bitter dig up multiple Healthstones. Notably, Bitter has a sassy personality, especially if you don't actually use any of the items he digs up.