The best dog shower brush brush depends on various factors such as the size of your dog, the thickness of its fur, and personal preference. Here are some popular options:

1. Furminator Deshedding Tool: It's a highly rated brush that removes loose fur while also massaging your dog.

2. JW Pet Gripsoft Double Row Undercoat Rake: This brush is designed to remove mats and tangles in thick fur.

3. Hertzko Self Cleaning Slicker Brush: The brush has fine wire bristles that effectively remove loose fur and tangles.

4. Kong ZoomGroom: It's a rubber brush that is gentle on the skin and effectively removes loose fur.

Ultimately, it's important to choose a brush that's comfortable for both you and your dog and effectively removes loose fur.