Is there a way to filter results by gravity delta range?

Yes, this feature is available for PRO members. Just expand the 'Gravity Delta' filters inside the 'Filter' control and input minimal and/or maximal values for any of the 1, 3, 7, 14, 30, 90-day gravity deltas.

ClickBank gravity delta filter

As a hint, you can efficiently use this feature with the Growing Vendors order.