Try out Wella Color Charm Permanent Liquid Hair Toner, a mild toner removing unwanted warmth or brassiness from blonde colors to achieve the desired look.
Colors:
T10 - Pale Blonde
T11 - Lightest Beige Blonde
T14 - Pale Ash Blonde
T15 - Pale Beige Blonde
T18 - Lightest Ash Blonde
T28 - Natural Blonde
T35 - Beige Blonde
42 - Warming Gold
50 - Cooling Violet