There are several kinds of feng shui evil spirits.

The first is the evil spirit of crystal.

Examples: obsidian, black tourmaline, lapis lazuli, cinnabar, etc.

The second is to open the light to ward off evil spirits.

In fact, there is no such good example. Basically, anything can ward off evil spirits as long as it is illuminated.

And the evil spirits here are actually spirituality above light.

Or it can be said that it is the spiritual strength of a monk.

The third is the folk evil spirits.

It's hard to study here, but the so-called word of mouth has its reasons.

Examples: Five Emperors' Money, Eight Diagrams Mirror, Taomu Sword, etc.

I hope I can help you.