I think Ice should gain resistances to Water, Fairy, and maybe Dragon. Water resists Ice, presumably because water's high thermal mass makes it highly resistant to temperature changes. Do you know what other material has this property? Water, when it's frozen. I think the resistance should be made mutual. Fairy and Dragon don't need strong flavor justifications (they don't for a lot of their type matchups), but the former would be a pretty significant buff for Ice at the expense of another top 3 type and the latter is an option if the first two buffs aren't enough. I think a flavor argument could be made for a Bug resist, but Bug doesn't need the hit, or an Electric resist, but I'd only consider that if the first three didn't pan out.