Found this set of earmuffs after including "polar fleece" in the search results.
Here is another pair available in the UK found by a different user.
I've been finding it difficult to find winter earmuffs that do not have fleece, cashmere, or fur (it appears as though "faux-fur" doesn't necessarily mean no fur).
This is an example of the style of earmuffs I'm looking for, that I have not been able to find.
Are there any examples of similar types of winter headgear that are vegan?