Water Deers are amazing I think! I don't know about the climate they live in though~

Elk are pretty cool if you like the look of them. They live around here where it gets very cold, plus they are hueg. There are a lot of subspecies you could check out! I like Roosevelt elk.
Manchurian Sika deer are cute but kind of small. They don't like snow much.
I like Atlas deer but they are found in warmer climates.

Seconding Sika! Cute. But maybe you should just do some loose concept sketches of lots of different deer to see what sticks with you. :)

The Whitetail and Mule deer tend to brave the rough, cold elements of America like champs. Elk are big and usually like to travel within herds, keeping out on glens and in valleys instead of in the forests like the Whitetail would.

Sikas are cute, yeah. I really like musk deer too. My partner is a fanatic for deer and knows a ton about them. I could see you as a caribou or elk easily, though. :) Good luck in your deer quest!

There's always the Irish elk, though they're extinct. I'm also a sucker for fallow deer; they have really cool antlers and naturally come in a wide variety of colors from white to almost black. Chital deer are also really cool, and I agree with the water deer. On a similar note, muntjacs are also really cool, but they're tiny.

If you like elk and caribou, maybe Thorold's/ white-lipped deer? They're darling and hardy.

Mmmm I think everyone's listed most of the larger deer. I personally have a soft spot for whitetails and elk (also note that Europeans call moose elk so if you want to avoid mixed google results, search for wapiti instead lol). I love the bushy neck manes on elk lol

Reindeer are lovely. Red deer such as myself are more majestic. Fallow deer are goofy and fun. Moose are powerful.

What about irish elk? Even without antlers, they were massive cervines that lived in colder climates.

Pronghorn are like North American antelope. I've seen them wild in upper Midwest so surely they operate in cooler climes akin to Whitetail