In SnowHorn Wastes
There are several unimportant SnowHorns in SnowHorn Wastes but there also is a GateKeeper called Garunda Te, a Blue SnowHorn who wants his Golden Root and a SnowHorn who helps Fox get forward after he has been recovered with Alpine Roots.
In DarkIce Mines
Several SnowHorns were trapped in DarkIce Mines before it floated to space. One of the most important SnowHorns must be saved from SharpClaws and then recovered with Alpine Roots. After this you can use him to smash a gate to a SharpClaw fortress where you find the Dinosaur Horn. With the horn you can summon a SnowHorn to carry you throughout a blizzard.