8-STOP VARIABLE ND FILTER(58mm-82mm) – Official 7Artisans Store
Amazon.com : K&F Concept 86mm Variable ND Filter ND2-ND32 Camera Lens Filter (1-5 Stops) No X Cross HD Neutral Density Filter with 28 Multi-Layer Coatings Waterproof (Nano-X Series) : Electronics
Amazon.com : Haida 77mm NanoPro Variable Neutral Density 1.2 to 2.7 Filter (4 to 9-Stop) : Electronics
Genustech 77mm Variable Neutral Density and Circular G-PND77 B&H
NiSi launches variable ND filter without the dreaded X-effect: Digital Photography Review