Some options for a backsplash to use with Grey Marble countertops are:

1. White subway tiles: This classic option complements the grey marble and gives a clean and timeless look.

2. Grey glass tiles: Choosing a grey glass tile backsplash can add depth and texture to your kitchen.

3. Metallic tiles: Silver or copper metallic tiles can create a modern and sophisticated look that will look great with grey marble countertops.

4. Patterned tiles: A patterned tile backsplash can add character and interest to a kitchen. Choose a pattern that complements the grey tones in the marble countertops.

5. Wood backsplash: Combining natural wood elements with grey marble creates a warm and cozy atmosphere. Consider using reclaimed wood to add a rustic touch.