Tomte/nisse predates Santa by a fair bit, closer to gnome than elf (Alv). Not sure why Anglos decided that Santa was associated with elves rather than gnomes though. You had to leave porridge out for the house gnomes to repay them for watching the animals (likely where Anglos got the milk and cookies from) or he’d fuck you up.

https://en.m.wikipedia.org/wiki/Nisse_(folklore)

Granted, elf was also used interchangeably for dwarves and elves until the 19th century.

Ah, interesting. TIL something new.

Same in Poland, note both shown mostly with western culture penetration in 80’s and 90’s, “elfy” is much more used in the context of fantasy elves from Tolkien, D&D etc. Small, faerie like creatures are most often called “wróżki” (lit. “fortune tellers”), while those christmas elves things but not particularly christmas, were very abundant in various roles in Slavic mythology and folklore under the broad name “skrzaty” (similar to the “tonttu” you mentioned i guess but not living only in homes). Slavic mythology don’t really have anything close to tolkien elves or their precursors irish sidhe, closest are nymphs and rusalki similar to nyphs and sirens of the greek myths.

There is also curious dichotomy between words “krasnoludki” and “krasnoludy”, the first being the diminutive form of the second, both meaning “dwarves” but the “krasnoludki” is broad mean for tiny mythical people while “krasnoludy” was only popularised by the first translation of Lord of the Rings and is used nearly exclusively for the fantasy dwarves (people with dwarfism are called “karły” which is also rarily used for fantasy dwarves).