The Elven Star
The Elven Star or seven-pointed star, is found in some branches of the Faerie tradition of Wicca. However, it has different names and can be associated with many other magical traditions.
In the Element Encyclopedia of Secret Signs and Symbols, the Elven Star (or Faerie Star) is also representative of the seven stars called the Pleiades. It is also a reminder that seven is a sacred number in many magical traditions -- it is connected with the seven days of the week, the seven pillars of wisdom, and many other magical theories. In Kabbalah, seven is connected to the sphere of victory. Aleister Crowley used a septagram as the emblem of his Order of the Silver Star.
In modern Pagan practice, this symbol can be used to keep information hidden from the prying eyes of the outside world. Use it on your Book of Shadows, to keep the contents safe, or on an amulent to prevent others from reading your thoughts.
Hecate's Wheel is a symbol used by some traditions of Wicca. It seems to be most popular among feminist traditions, and represents the three aspects of the Goddess -- Maiden, Mother and Crone. This labyrinth-like symbol has origins in Greek legend, where Hecate was known as a guardian of the crossroads before she evolved into a goddess of magic and sorcery.
According to fragmentary texts of the Chaldean Oracles, Hecate is connected to a maze which spiralled around like a serpent. This maze was known as the Stropholos of Hecate, or Hecate's Wheel, and refers to the power of knowledge and life. Traditionally, a Hecate-style labyrinth has a Y in the middle, rather than the typical X shape found at the center of most labyrinths.
Images of Hecate and her wheel have been found on first-century c.e. curse tablets, although there seems to be some question about whether the wheel shape itself is actually Hecate's domain or that of Aphrodite - there was some occasional overlap of goddesses in the classical world.