Want to know what all the new cards in Tomb of Ice do? Look no further. Obviously, spoilers abound.

Heroes
Format is Life/Fatigue/Armor/Speed

Shiver
12/4/0/4
3 Magic Dice
3 Wizardry Skills
During the overlord's turn, Shiver has the Aura 4 ability.
Conquest: 3

Okaluk and Rakash
16/2/0/6
2 Melee Dice, 1 Ranged Die
2 Fighting Skills, 1 Subterfuge Skill
Okaluk and Rakash have the Stealth ability.
Conquest: 3

Arvel Worldwalker
12/4/1/4
1 Melee Die, 1 Ranged Die
2 Fighting Skills, 2 Subterfuge Skills
When a glyph has been activated, Arvel may draw 2 feat cards instead of just 1. Arvel's maximum feat hand size is increased to six.
Conquest: 3

Laughin Buldar
16/3/1/4
3 Melee Dice
3 Fighting Skills
Laughin Buldar may use a single two-handed melee weapon as if it were a one-handed weapon.
Conquest: 4

Karnon
16/4/1/4
5 Melee Dice
2 Fighting Skills
Karnon has the Tread Ice ability, and is immune to Frost and Fear.
Conquest: 4

Zyla
8/5/0/4
1 Melee Die, 1 Ranged Die, 1 Magic Die
1 Fighting Skill, 1 Subterfuge Skill, 1 Wizardry Skill
Zyla has the Fly and Ghost abilities. Enemy figures can move through Zyla, but cannot end their movement in the space she occupies.
Conquest: 1

Monsters
Stats listed are for the 2 or 3 player cards. For 4 players, add 1 life; for five players, add yet another.
Format is Speed/Life/Armor

Shade
4/3/1
Magic: White, Yellow
Ghost, Stealth, Fly, Pierce 2
Master Shade
5/4/2
Magic: White, Yellow, Black
Ghost, Stealth, Fly, Pierce 4

Lava Beetle
3/3/2
Ranged: Blue, Green
Blast 1
Master Lava Beetle
3/4/3
Ranged: Blue, Green, Black
Blast 1, Burn

Medusa
4/4/2
Magic: White, Green, Yellow
Stun
Master Medusa
4/5/3
Magic: White, Green, Yellow, Black
Stun, Quick Shot

Wendigo
5/4/3
Melee: Red, Green, Black
Stealth, Reach, Tread Ice
Master Wendigo
5/5/3
Melee: Red, Green, 3 Black
Stealth, Reach, Tread Ice

Ice Wyrm
4/8/3
Ranged: Blue, 2 Green, Black
Tread Ice, Ghost
Master Ice Wyrm
4/9/4
Ranged: Blue, 2 Green, 2 Black
Tread Ice, Ghost, Swallow

Feat Cards
Fighting

Follow Through (3x)
Play after making a sucessful melee attack on a monster (a melee attack that doesn't miss).
Gain +2 damage for that attack.

Fend (3x)
Play this card after the overlord has declared a monster's attack against you, but before he has rolled the dice for the attack.
Your hero gains +4 armor for that attack.

Lunge (2x)
Play before rolling the dice when making a melee attack.
You gain the Reach ability for that attack.

Hurry (2x)
Play at the start of your turn.
You may make 1 extra melee attack this turn.

Riposte (2x)
Play after a monster has attacked you with a melee attack.
If able, you may immediately attack the monster.
After your attack, the overlord resumes his turn as normal.

Blocked (2x)
Play after a monster has made a sucessful melee or ranged attack against you (a melee or ranged attack that doesn't miss).
You must roll a power die. If the result is a surge there is no effect.
If the result is not a surge, that monster's attack against you becomes a miss.

Sweeping Blow
Play before rolling the dice when making a melee attack.
You gain the Sweep ability for that attack.

Second Wind
Play at the start of your turn.
Recover all of your fatigue.

Killing Blow
Play after rolling the dice in a melee attack.
The hero chooses the results of that attack roll, placing those sides of the dice faceup, except that the hero cannot change the facing result of the red die.

Subterfuge
Hustle (3x)
Play at the start of your turn.
Your hero may move 3 extra spaces this turn.

Shooting for Distance (3x)
Play before rolling the dice when making a ranged attack.
You gain +8 range for that attack.

Disarm (2x)
Play when the overlord plays a trap card on you or any friendly figure within 3 spaces of you.
You must roll a power die. If the result is a blank, there is no effect.
If the result is not a blank, the trap card is canceled and discarded, but the overlord must still pay the threat cost of the discarded trap.

Foiled Plans (2x)
Play at the start of your turn.
Randomly pick and reveal 2 cards from the overlord's hand.
The overlord must choose 1 of those 2 cards to discard, and returns the other card to his hand.
The overlord does not recieve threat tokens for the discarded card.

Evade (2x)
Play after a monster has made a sucessful ranged or magic attack against you (a ranged or magic attack that doesn't miss).
You must roll a power die. If the result is a surge, there is no effect.
If the result is not a surge, that monster's attack becomes a miss.

Backstab (2x)
Play this card after the overlord has declared a monster's melee attack against you, but before he has rolled the dice for the attack.
You must roll a power die. If the result is a surge, there is no effect.
If the result is not a surge, you may make a melee or ranged attack against that monster before the overlord attacks you with that monster.

Skulk
Play this card after the overlord has declared a monster's melee attack against you, but before he has rolled the dice for the attack.
You must roll a power die. If the result is a surge, there is no effect.
If the result is not a surge, you gain the Ghost and Stealth abilities until the start of your next turn.
Leave this card faceup in front of you until the start of your next turn.

Chink in the Armor
Play before rolling the dice when making a ranged attack.
You gain the Pierce 4 ability for that attack.

Second Wind
Play at the start of your turn.
Recover all of your fatigue.

Wizardry
Focus (3x)
Play before rolling the dice when making an attack.
Gain 2 free surges when making that attack.

We Are Not Afraid (3x)
Play at the start of any player's turn (including the overlord.)
The overlord loses 4 threat.

Protect Thyself (2x)
Play this card after the overlord has declared a monster's attack against any hero, but before he has rolled the dice for the attack.
Your hero, and all the heroes within 3 spaces of you, gains +2 armor until the start of your next turn.
Leave this card faceup in front of you until the start of your next turn.

Carried By Air (2x)
Play at the start of your turn.
You gain +2 speed and the Fly ability until the end of this turn.

Transparent (2x)
Play this card after the overlord has declared a monster's attack against any hero, but before he has rolled the dice for the attack.
You gain the Stealth ability for that attack.

Sparks of Pain (2x)
Play this card at the start of the overlord's turn.
You gain the Aura 4 ability until the start of your next turn.
Leave this card faceup in front of you until the start of your next turn.

Flaming Fury
Play after making a sucessful magic attack on a monster (a magic attack that doesn't miss).
Place three burn tokens on that monster.

Magi Madness
Play before rolling the dice when making a magic attack.
You gain the Sorcery 3 ability for that attack.

Preventing Evil
Play this card immediately after the overlord has played a card from his hand. You must roll a power die. If the result is a surge, there is no effect.
If the result is not a surge, the overlord's card is not put into play and is discarded instead.
The overlord does not have to pay the threat cost of the discarded card and does not get threat tokens from discarding that card.

Treasures
Copper
Treasure Cache
Receive 1 invisibility potion and draw another card from this deck.

Screaming Eagle Staff
Weapon (2 hands)
Magic
Breath
Can spend 2 surges for +1 damage
White, Yellow

Leviathan
Weapon (2 hands)
Melee
You must roll the stealth die when making a melee attack with this weapon. Can spend 1 surge for +1 damage.
Red, 2 Green

Ripper
Weapon (1 hand)
Ranged
Pierce 2. When making Ranged attacks with this weapon, you may reroll a single attack die.
Blue, Green, Yellow.

Silver
Treasure Cache
Receive 50 coins and 1 invisibility potion and draw another card from this deck.

Beastman Fetish
Other
Once during your turn, you may reroll a single die.

Bow of the Hawk
Weapon
Ranged (2 hands)
Pierce 3. When making ranged attacks with this weapon, you may reroll a single attack die.
Blue, 2 Green, Yellow

Lifedrinker
Weapon (2 hands)
Melee
If you kill a monster when making a melee attack with this weapon, you recover 1 wound. Can spend 1 surge for +1 damage.
Red, 2 Green

Gold
Treasure Cache
Receive 150 coins and 1 invisibility potion and draw another card from this deck.

Stone Cutter
Weapon (2 hands)
Melee
You must roll the stealth die when making a melee attack with this weapon. Can spend 1 surge for +2 damage. Can spend 2 surges for +5 damage.
Red, 2 Green, 2 Yellow

Red Plate of Kellos
Armor
+3 Armor
If you recover fatigue by resting, you may also recover 3 wounds.
Your base speed is reduced to 4.

Star of Kellos
Weapon - Rune(1 hand)
Magic
Monsters within 6 spaces of you lose the Undying ability. Can spend 1 surge for +1 damage or +1 range.
White, 2 Green, Yellow

Other

There is also a relic called Ring of Rogues. It is an Other item which grants you Stealth and gives you +1 damage.

The overlord cards and anything related to Road to Legend are not listed here as I am not familiar enough with it.

Finally, there are two new store items:
Hammer
Weapon (2 hands)
Melee
Knockback. Can spend 2 surges for +1 damage.
Red, Green
100

Morning Star
Weapon (1 hand)
Melee
Can spend 3 surges for +1 damage. Off-hand bonus: +1 damage and 1 free surge.
Red, 2 Yellow
75

Conclusion
So what do I think of all of this?
I love that the heroes are so different from past expansions. A hero worth 1 conquest, a hero with 5 power dice, a hero with 4 skills, etc. I like how creative they got.
The monster sculpts look great and I love their new powers.
Feat cards are very, very powerful. I would not recommend adding them to scenarios the heroes are breezing through already. You could also consider only giving them to heros when the flip glyphs, rather than giving them some at the start as well.
Stealth is thematic and used by heroes and monsters alike. However, it does make the game take longer by making things harder to kill. Ice, similarly, can make heroes lose whole turns. Making Descent slower seems a step in the wrong direction to me.
All in all, kind of a mixed bag, but still recommended.