I have a $200 Best Buy gift card. I am thinking I want a really nice ND filter, but not sure. Best Buy has a large selection of camera gear on line (unlike in store).
I carry a 5Diii, Tamron 70-200 2.8, and a Canon 24-70 2.8 (both 77mm lenses).
I am also thinking about getting a 2x converter. They have an off brand for $160.