Now here's an interesting, and confusing, shred of lore that stumbled upon me recently. I was at a memorial service for an extended family member. Some of the folks who were in attendance were elderly Deitsche with whom I had not personally been acquainted.
Somehow the topic of the Frost Giants' Wonnetzeit attack came up, and one of the elderly women asked me if I knew much of Riebzaahl ("turnip count") or Riewezaahl ("turnips count"). I had not heard of this being prior to this conversation, and she told me she remembered from her youth her mother talking about Riebzaahl. She said that her mother described Riebzaahl as a irritable Mountain Giant who has a strong ability to bring about unstable weather and would occasionally simply cause trouble because "that is what Giants do."
So, stepping back from the Deitsch names, I found the German-language Rübezahl in Silesian legends (which makes sense as there is a strong historical Silesian presence among the Deitsch in the particular area I was in). Although some of the information I am coming across treats him like a god, but even more information indicates that he is not a pleasant spirit and has more attributes that would place him among the Giants.
The lore emanates mostly from the Germans and Slavs of Silesia and Bohemia. Grimm (Volume II, p. 480) refers to him as a wood-sprite and has some notes regarding him that may link him to Knecht Ruprecht, but there is not an ample description there.
That being said, I am sure many Germans, Czechs, and Poles may have more familiarity with the tales of this being. I am interested to find out how widespread this knowledge is in the Deitsch and other cultures.