Here is idea for fey dire wolves and named one,
Hallava
Hallava the Grey Fur
Huge Fey (beast), Neutral
Armor Class 17 (Steely Fur)
Hit Points 95 (10d12 + 30) Speed 50 ft.
STR 20(+5) DEX 15(+2) CON 16(+3) INT 10(+0)
WIS 14(+2) CHA 12(+1)
Saving Throws Str +7, Con +5
Skills Perception +4, Stealth +4
Damage Immunities Cold
Senses Blindsight 10 ft., Darkvision 60 ft.,
Passive Perception 14
Languages Understands Common and Sylvan but cannot speak
Challenge 4 (1,100 XP) Proficiency Bonus +2
Steely Fur. Hallava's fur is as dense as tempered steel. Nonmagical attacks that deal slashing damage made against Hallava are reduced by 3.
Keen Hearing and Smell. Hallava has advantage on Wisdom (Perception) checks that rely on hearing or smell.
Pack Tactics. Hallava has advantage on an attack roll against a creature if at least one of Hallava's allies is within 5 feet of the creature and the ally isn't incapacitated.
Actions
Bite. Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 14(2d8 + 5) piercing damage plus 7(2d6) cold damage. If the target is a creature, it must succeed on a DC 15 Strength saving throw or be knocked prone.
Freezing Howl (Recharge 5–6). Hallava releases a bone-chilling howl. Each creature within a 30-foot radius of Hallava must make a DC 13 Constitution saving throw. On a failed save, a creature takes 21 (6d6) cold damage and its speed is halved until the end of its next turn. On a successful save, a creature takes half as much damage and its speed is not reduced.
Reactions
Rime Coat. When a creature hits Hallava with a melee attack while within 5 feet of it, a cloud of magical frost bursts from Hallava's fur. The attacker takes 4 (1d6) cold damage.
Lore & Unique Traits
Ancient Bloodline
Hallava’s appearance is deeply altered by ancient fey energy and its metallic fur, meaning it does not resemble a normal animal at first glance. A character must succeed on a DC 18 Intelligence (History) or Wisdom (Nature) check to recognize that Hallava belongs to an ancient, mythical bloodline of giant fey dire wolves.
Winter Guardian's Passage
Hallava can move through any snowy, icy, or difficult forest terrain without expending extra movement. It leaves behind no physical tracks or scent while moving unless it chooses to. It gains a +10 bonus to Dexterity (Stealth) checks when attempting to hide in a wintry forest setting.
Illusory Tracks
Hallava can choose to leave large wolf prints in the snow that glow with a faint, magical frost light (detectable as magical with Detect Magic or a DC 15 Wisdom (Survival) check).
The Path of Respect (Out of the Forest): If the adventurers have shown respect toward the forest and its spirits, the tracks guide them safely out of the wild or directly onto the path they were looking for.
The Path of Disrespect (Into a Trap): If the characters have defiled nature or angered the fey, the tracks lead them into a dangerous trap. The characters must succeed on a DC 15 Wisdom (Survival) check to realize they are being misled. On a failure, the party falls into an ambush (e.g., thin ice, avalanche danger, or surrounded by Hallava and forest spirits) and is surprised when combat begins.
Magic Item: Hide of Hallava
Armor (hide or leather) or Wondrous Item (cloak), rare (requires attunement)
This exceptionally dense, steel-gray pelt shimmers with a silver sheen and was harvested from the winter guardian of the ancient primeval forest. The fur feels cool to the touch, but it perfectly insulates its wearer from the freezing world outside.
Winter's Protection (Cold Immunity): You have immunity to cold damage. Additionally, you suffer no ill effects from extreme cold environments and cannot gain exhaustion from freezing weather.
Steely Defenses (Slashing Resistance): The metallic density of the fur absorbs sharp cuts. You have resistance to slashing damage.
Adventure Hook: Crafting the Hide
Because Hallava's pelt is woven with fey magic and steel-like hairs, an ordinary village cobbler cannot shape it into usable gear. To utilize the Hide of Hallava, the players must embark on a crafting quest:
Find a Master Artisan: They must seek out an elven smith, a dwarven master weaver, or a powerful fey creature who knows the ancient secrets of working mythical pelts.
Obtain Specialized Tools: Ordinary shears and knives will dull or snap against the steel fur. The characters need magical tools or extraordinary heat, such as dragon breath or a specialized elemental forge, to cut and shape the pelt.