I think a Polar Animal pack is more likely than another arctic pack, but that said, my picks for a pack like that would be:
1. Musk Ox
2. Walrus
3. Sea otter
4. Snowy owl (if not, because aviary birds are not allowed then king eider)
5. Wolverine
6. Atlantic puffin
7. Harp seal
8. Siberian newt (maybe????)
If we are going with a polar pack which would include antarctica as well then i would change this to:
1. Musk ox
2. Wolverine
3. Sea otter
4. Rockhopper penguin ( i think this one is the most unique of the antarctic species of penguin, but i would love megallanic or gentoo as well)
5. Atlantic puffin
6. Harp seal or Walrus (probably the latter since again, is more interesting than just another seal)
7. King eider
8. Newt (or any antarctic sea creature that could fit in a tank lol)
So pretty much the same list but with a penguin lol