There were actually ice trolls in Baldur's Gate 2 somewhere (easily destroyed).
Anyway, I created two new frigid icons: the remorhaz and the polar bear (as well as a cheap-o brown bear recolor - yeah, it looks fat, but whatever
).
Interestingly, MMII says that the polar bear is 14' long, but that is ludicrous - as usual, for real-life stuff, I simply make the icons at scale to their real-life counterparts, so it is at a normal 9' long or so.
(Convenient for cheap-o recolors, since brown bears are also 9' long or so.)