Some opinions are that a yellow bulb gives better clarity than white or blue:

"Illuminate your fog lights with the 9006 Sylvania Yellow Fog Light Bulbs. These halogen light bulbs have a wattage of 55W and a voltage of 12V, suitable for any fog light. The bulbs come in a pack of two with the OE/OEM part number 9006 and the manufacturer part number 9006FV.BP2.

These bulbs are perfect for those who want to upgrade their fog lights and have a yellow light color for a cozy and warm atmosphere. The packaging includes everything you need to install the bulbs, making it easy to replace your old bulbs. Get the 9006 Sylvania Yellow Fog Light Bulbs and enhance your driving experience with better visibility during low visibility conditions."

Can ship almost anywhere