Witchy tools: athame.
In the Celtic mythic traditions, the knife is always paired with the earth element, the sword and the stone, sword and shield, and so on. Swords are fused with powerful abilities and spirits and are magical beings in their own rights.
That being said. I have not found the athame for me yet. I want one that is very simple and unfinished wood so that I can decorate the handle myself and stain it with ebony wood stains.
Other than that I just use scissors and kitchen knives around the house. I use gardening shears outside. So for now the need for special knives or daggers has not come up. However, I am starting to take more of interest in athames and so I will keep a lookout for The One for me.