Places to farm for Ice Holiday currency. Non-italicised are Ice, italicised are Neutral. Only areas with Ice enemies are listed.
Training Fields - Crimson Emperor, Amaranth Moth
Woodland Path - Bluefin Charger, Crimson Emperor, Wildwood Owl
Scorched Forest - Wintermane Bowman, Red-Winged Owlcat
Sandswept Delta - Scaleback, Peacock Scorpion
Bamboo Falls - Ethereal Trickster, Tengu
Waterway - Cumulus Seal, Rainbow Sprite, Radioactive Slime
Arena - Silver Springbok, Charcoal Sprangyroo, Chimera, Double-Tailed Warcat
Boreal Wood - Coarsefur Yeti, Hoarfrost Mauler, Permafrost Impaler, Silver Springbok, Winter Wolf
Harpy’s Roost - Snow Streak, Dodo
Mire - Mistwatch Shellion. Shellion
Kelp Beds - Mantarune, Manatee
Golem Workshop - Frost Delver, Steelhound
Looks like the best places are the Boreal Wood and Arena.
For additional information: Ice Festival - Currency and Chests