Vegetable fermentation is spontaneous or wild fermentation. To start it, you don't need anything other than fresh vegetables and good rock salt - possibly some water and a vessel in which the vegetables can ferment in the absence of oxygen.
If you're just getting started with fermenting, I recommend reading up a bit first - then you'll also know which vessels are suitable and what to look out for to produce delicious and safe food.
Afterwards, you can safely ferment any vegetable. I have written down many tasty recipes for vegetable ferments for you.