white lady by wella. I tried silver lady before, but it turned kinda greyish b/c it's an ashy green tone :/ It depends on what color you want to tone down. white lady tones down yellow b/c it has purple tones & silver lady has blue/green tones to tone down orange. After using a toner, I'd recommend keeping your hair less brassy by using a violet shampoo conditioner such as shimmer lights.
I use white lady it makes my hair kinda silver.
Use a silver shampoo. It is kind of expensive where I live and I have long hair so I just buy some Gentian Violet and mix it with my shampoo. It's really cheap and works wonders. Just be careful not to throw too much in your shampoo as your hair can come out grey or purple. I usually test if it's mixed in the right quantities by throwing some on toilet paper and rubbing it, if it is a light purplish color then I know it's good :)