A Northern Hemisphere winter is the popular version in fantasy RPGs and the 'traditional' setting for Christmas. It is a time of snow, darkness and shelter for remote human populations against the figurative and literal wolves of the leanest season. The harvest may be in, and an opportunity for feasting available to mark midwinter's passing, but in all it is a harsh season, and an isolated homestead might appreciate help - any help, from friendly beings.
In Scandinavian folklore this is the Nisse or Tomte, a small humanoid creature who lives alongside countryfolk, helping (usually) invisibly as a quiet labourer, mender, and guardian of the homestead. They are, in that regard, akin to Brownies or Leprechauns, or perhaps the fairy tale elves from The Elves and the Cobbler; to be respected and occasionally appeased (but not flattered) lest that helping hand turn into a harmful one.
The equation is obviously closer to those aforementioned domestic helpers, but interestingly, by description the Tomte is very close to the Gnome: tall, pointed hat, long beard, very small, and seemingly able to either disappear or blend into the background at will. A useful natural talent to have - perhaps mechanically close to a Thief's Hide in Shadows skill. Might be useful to appropriate . The Tomte also gives the Gnome that essential niche of straddling the worlds of nature and civilisation: domestic without being domesticated, civilised without being a part of human civilisation.
In the Christmas lore of Scandinavia, the Tomte has been enhanced as a representative of midwinter or, in particular, Christmas. In its male appearance (and they are very usually male) it resembles Santa Claus, and is credited with gift giving, charity and the goodwill of strangers for the harshest season. As capricious as the Tomte or Nisse may be, this can embody much of the civil nature of the Gnome, giving the Gnome an additional 'hook' in his RPG identity - and a sense of time and location in a fantasy human world.
