To kick this place off I am posting some information on Hecate here.
Hecate, Hekate (Hekátē), or Hekat was originally a goddess of the wilderness and childbirth originating from Thrace, or among the Carians of Anatolia . Popular cults venerating her as a mother goddess integrated her persona into Greek culture as 'Εκατη. In Ptolemaic Alexandria she ultimately achieved her connotations as a goddess of sorcery and her role as the 'Queen of Ghosts', in which guise she was transmitted to post-Renaissance culture. Today she is often seen as a goddess of witchcraft and Wicca.
Other names and epithets
* Chthonian (Earth/Underworldgoddess)
* Crataeis (the Mighty One)
* Enodia (Goddess of the paths)
* Antania (Enemy of mankind)
* Kurotrophos (Nurse of the Children and Protectress of mankind)
* Artemis of the crossroads
* Propylaia (the one before the gate)
* Propolos (the attendant who leads)
* Phosphoros (the light-bringer)
* Soteira ("Saviour")
* Prytania (invincible Queen of the Dead)
* Trioditis (gr.) Trivia (latin: Goddess of Three Roads)
* Klêidouchos (Keeper of the Keys)
* Tricephalus or Triceps (The Three-Headed)
Goddess of the crossroads
Hecate had a special role at three-way crossroads, where the Greeks set poles with masks of each of her heads facing different directions 
The crossroad aspect of Hecate stems from her original sphere as a goddess of the wilderness and untamed areas. This led to sacrifice in order for safe travel into these areas. This role is similar to lesser Hermes, that is, a god of liminal points or boundaries.
Hecate is the Greek version of Trivia "the three ways" in Roman mythology. Eligius in the 7th century CE reminded his recently converted flock in Flanders "No Christian should make or render any devotion to the gods of the trivium, where three roads meet, to the fanes or the rocks, or springs or groves or corners", acts the Druids often did. see Hectite: 
Goddess of sorcery
The goddess of sorcery or magic is Hecate's most common modern title.
Traditionally, Hecate is represented as carrying torches, very often has a knife, and may appear holding a rope, a key, a phial , flowers , or a pomegranate .
The torch is presumably a symbol of the light that illuminates the darkness, as the Greeks secured Hecate in her role as the bringer of wisdom. Her knife represents her role as midwife in cutting the umbilical cord (possibly symbolized by the rope), as well as severing the link between the body and spirit at death. The key is significant to Hecate's role as gatekeeper, being the one who could open the doors to sacred knowledge. The Orphic Hymns list her as the "keybearing Queen of the entire Cosmos." The pomegranate was seen by the Ancient Greeks as the fruit of the underworld, though it was also used as a love-gift between Greek men and women. This may be because a pomegranate was eaten by Persephone, binding her to the underworld and to Hades.
In the so-called "Chaldean Oracles" that were edited in Alexandria, she was also associated with a serpentine maze around a spiral, known as Hecate's wheel (the "Strophalos of Hecate", verse 194 of Isaac Preston Cory's 1836 translation). The symbolism referred to the serpent's power of rebirth, to the labyrinth of knowledge through which Hecate could lead mankind, and to the flame of life itself: "The life-producing bosom of Hecate, that Living Flame which clothes itself in Matter to manifest Existence" (verse 55 of Cory's translation of the Chaldean Oracles).
The she-dog is the animal most commonly associated with Hecate. She was sometimes called the 'Black she-dog' and black dogs were once sacrificed to her in purification rituals. At Colophon in Thrace, Hecate might be manifest as a dog. The sound of barking dogs was the first sign of her approach in Greek and Roman literature. The frog, significantly a creature that can cross between two elements, is also sacred to Hecate . As a triple goddess, she sometimes appears with three heads-one each of a dog, horse, and bear or of dog, serpent and lion.
During the Medieval period in western Europe, Hecate was reverenced by witches who adopted parts of her mythos as their goddess of sorcery. Because Hecate had already been much maligned by the late Roman period, Christians of the era found it easy to vilify her image. Thus were all her creatures also considered "creatures of darkness"; however, the history of creatures such as ravens, night-owls, snakes, scorpions, asses, bats, horses, bears, and lions as her creatures is not always a dark and frightening one. (Rabinowitz)
Plants and herbs
The yew, cypress, hazel, black poplar, cedar, and willow are all sacred to Hecate .
The leaves of the black poplar are dark on one side and light on the other, symbolizing the boundary between the worlds. The yew has long been associated with the Underworld.
The yew has strong associations with death as well as rebirth. A poison prepared from the seeds was used on arrows , and yew wood was commonly used to make bows and dagger hilts. The potion in Hecate's cauldron contains 'slips of yew'. Yew berries carry Hecate's power, and can bring wisdom or death. The seeds are highly poisonous, but the fleshy, coral-colored 'berry' surrounding it is not. If prepared correctly, the berry can cause visual hallucinations (Ratsch).
Many other herbs and plants are associated with Hecate, including garlic, almonds, lavender, thyme, myrrh, mugwort, cardamon, mint, dandelion, hellebore, and lesser celandine. Several poisons and hallucinogens are linked to Hecate, including belladonna, hemlock, mandrake, aconite (known as hecateis), and opium poppy. Many of Hecate's plants were those that can be used shamanistically to achieve varyings states of consciousness.