Chalk is carried to draw symbols for use in incantations and protection.
Dead Man's Blood
Used as a poison for vampires, the boys didn't always carry this with them, but have now started doing so. They carry it in a syringe for ease of use.
Bela had this above her door. It is a plant used for holding Hellhounds at bay. Part of the Viburnum family, it is part of the honeysuckle family and is often used medicinally to ease menstrual cramps.
Goofer dust, which is made from a combination of various ingredients, including graveyard dirt, sulphur powder, salt, powdered bones, rattlesnake skin and powdered herbs, is used to keep the Hell Hounds at bay. Dean and Sam fist encountered it in Crossroad Blues but have since kept it as a standard piece of equipment.
Water that has been blessed by a priest is said to have special properties, one of which is that it burns like acid when it touches a demon. This is a very quick way of identifying whether someone has been possessed by a demon, although some demons can be powerful enough that the Holy Water doesn't affect them.
Holy wood from Peru, the Palo Santo is toxic to demons, in the same way that Holy Water is. It was used by Tamara and Isaac as one of their primary hunting tools and have their sharpened into a pointed stake.
Rock Salt is also known by its scientific name of Halite. It is the mineral form of sodium chloride (salt) and is formed in isometric crystals. It can vary in colour from colourless to light or dark blue and pink. In the ghost hunting world it is used as a projectile (bullet) in guns in order to hold back ghosts and spirits.
Other than in rock form, salt is also used as a barrier. Poured around windows and doors, it can prevent a spirit or demon from entering the room.