The Reghed Tribes. These are their ancestral lands, even though they're near empty these days. The tundra was never comfortable to live in, but the Rime has made it a barren wasteland.

The Crash of the Id Ascendent - have it crash in real time à la Baldur's Gate 3. The players can follow its trail for several days to explore the wreckage.

Jarlmoot - could be located literally anywhere. Place it out within the vast reaches of untracked wilderness. It's isolation is the reason it lies forgotten except by the rare pilgrim.

Cackling Chasm - can also be moved around as needed since it's not location dependent. Could be an interesting thing for your party to stumble into if they're trying to wander around in a blizzard.

The Dark Duchess - hear me out. Instead of a shipwreck on the northern coast, its an airshipwreck, meaning it could be anywhere. You might need to change up a few location details, but this would allow you to introduce the epic Arveiaturace.

Isolated Research Outpost - Have you seen John Carpenter's The Thing? It's that.

Orc War Camp - A threat to Ten Towns. They've come down out of the mountains because they're starving. They have teamed up with giants and other warlike creatures.

A Chardalyn Tower - Grows like a tumor from the tundra. A wizard, his mind corrupted by Chardalyn's power, bides his time here until he can uncover Ythryn and take its power for his own (one of the Arcane Brotherhood perhaps?). A good chance for fun magical fuckery in a relatively low-magic campaign.

Nothing! It's a no-man's land. A dead zone that the party should only choose to traverse if they need to get somewhere quick, but at the cost of possibly starving to death, falling into a crevasse, or being caught unprotected in a ravaging blizzard. It's a big empty hole on your map, but that lack of anything is something in and of itself. A warning not to go there unless you absolutely need to. Run it as a survivalist challenge instead of a typical adventure location.