Berchta, also called Perchta, is a goddess of southern Germany and Austria who later became known in folklore as a kind of boogeyman who would frighten children. Modern Heathens look to a variety of sources to understand her as a goddess and so the understandings of her can vary widely.
In modern folklore Berchta/Perchta is seen as a lesser spirit who punishes miscreants and who has an assortment of fairy beings called Perchten who travel with her. Perchten is also a word used to describe masks worn during processions, called Perchtenläufe, to drive out evil spirits (Wagner, 2014). These masks are made of a variety of material and usually take the form of grotesque animals; they appear in two styles, schiachperchten (ugly perchten) and schönperchten (beautiful perchten) (Wagner, 2014). Ugly perchten drive out evil spirits while beautiful perchten bring luck (Wagner, 2014). The ugly perchten are also associated with the Krampus traditions in modern times as the masks are reminiscent of the appearance of Krampus (Muller, 2002).
In the older material she was almost certainly a goddess, similar in many ways to Frau Holda; in fact some people believe the two are the same being under different names. Berchta appears in those areas of Germany where Holda does not lending some credence to this idea, and the two are both associated with the Wild Hunt and caring for the souls of dead children (Grimm, 1888). Both are also associated with Yule and with spinning and also have in their retinue fairy beings - perchten with Perchta (Berchta) and huldufolk with Holda. Both Holda and Berchta are also associated with the wagon and the plow and both are associated with witches (Grimm, 1888). However there are notable differences as well, and these are enough to persuade me that the two are separate, albeit likely related, beings.
Berchta's name means bright, luminous and it is said she appears dressed in white (Grimm, 1888). Berchta received offerings on rooftops and she is associated with specific foods (Heath, 2013). Grimm discusses a fish and dumpling dish as well as oatmeal dish connected to Berchta, which her followers would eat on the last night of Yule (Grimm gives her feast day as either December 25th or January 6th; in modern practice it is usually December 31st); those who failed to observe this practice were severely punished (Grimm, 1888). Berchta was also strongly connected to iron and said to have a nose made of this metal (Heath, 2013). In many of Berchta's stories she is said to be accompanied by either the fey perchten or by the ghosts of young children called heimchen (literally "crickets"), which she cares for; these spirits are said to bring rain to the earth while she tends her own realm, or as Grimm says "while she worked underground with her plough". (Grimm, 1888). Besides being associated with agriculture Berchta is also associated at least tentatively with streams and rivers, as in one story where she sets an arrogant woman to spinning and the resulting thread on its spools is thrown into a stream to give it back to Berhcta (Grimm, 1888). Berchta is known to reward those who help her, usually by giving them the archetypal fairy gift of a useless seeming object - in this case wood chips - which turn to gold. She also punishes those who offend her, typically by cutting them open and stuffing their body with straw, although in some stories she forces them to spin, blinds them, or, as in one tale from Bavaria, she hits a greedy man with an ax (Grimm, 1888). In older material she is described as gentle and generous, a kind Goddess who appears clad in white to care for babies while the adults sleep; indeed Grimm calls her "the White Lady" (Grimm, 1888).
Some people believe that Berchta evolved from the older Germano-Gaulish goddess Bricta (Brixta) who was a goddess of healing (Heath, 2013). Bricta was known in Luxeuil France, not too far from the border of what is now south western Germany. Bricta may mean either "shining one" or "magic, enchantment" and she was associated with both healing and cursing, and possibly with the river Breuchin which might be named after her (Etymology, n.d.). This means that not only are the names possibly connected in their meanings but both also have connections to water, specifically streams or rivers. If we give weight to this idea then Berchta could also be seen as a healing Goddess in a German heathen context.
My own journey to honoring Berchta has been a strange one. Last year, as I was working on my health after a couple brushes with near-death I started to have experiences with a being I called the White Lady who answered when I was praying for healing. I had no idea who she was, and slowly figured out that she wasn't any of the deities I might have expected - not Airmed or Eir for example. The closest I came to someone that "felt" like what I was experiencing was Urglaawe's Weisskeppich Frau, but it wasn't quite her. After a while I suspected that she was Berchta, but reading about her I didn't see anything relating to healing; finally though I decided to go with my gut and honor my Berchta as my White Lady and simply view the healing aspect as a unique upg. And just after coming to that conclusion I ran across the idea that Berchta was actually related to or derived from the older Celtic Goddess Bricta who does have healing associations and that really clicked for me. So I honor Berchta in part as a goddess of healing, as well as a deity who protects babies and children and has ties to the Hidden Folk.
Grimm, J., (1888) Teutonic Mythology
Heath, C., (2013) From Fairytale to Goddess: Frau Holle and the scholars that try to reveal her origins. Retrieved from https://www.academia.edu/3548067/From_Fairytale_To_Goddess_Frau_Holle_And_The_Scholars_That_Try_To_Reveal_Her_Origins
Etymology (n.d.) retrieved http://theses.univ-lyon2.fr/documents/getpart.php?id=lyon2.2009.beck_n&part=159248
Muller, F and U (2002) Percht und Krampus. Retrieved from http://archive.today/g2uJi
Wagner, A., (2014) Perchtenlaufe: Salzburg's pagan heritage. Retrieved from http://www.visit-salzburg.net/travel/perchten.htm