Answer:
This depends entirely on the witch. If he or she are interested in herbal magical practices, they may own a mortar and pestle, censer, charcoal blocks, herbs and essential oils, and other things they'll need like books about herb and essential oils.
A witch who is called to stones and crystals may have a large stone and gem collection whereas a witch called to scrying and divination may own a pendulum, runes, and Tarot cards.
There are no 'set' accessories; if you don't have one thing or another, it doesn't mean you aren't a witch. You can have whatever pleases you and works best.
They also have hats and broomsticks!
To the above - Most people have hats of various kinds, not just witches, and most witches call a broom a besom.