OConnor Step-Down Clamp Ring (150-95mm) C1243-1125 B&H Photo
Anamorphic Lens Clamps — Vid-Atlantic Media Productions
Amazon.com : NEEWER Mini Follow Focus with A/B Stops, Lens Gear Ring, 15mm Rod & Rod Clamp for Cinema Camera, DSLR/Mirrorless Camera, Compatible with Lens Diameter Up to 114mm, PG001 (Silver) :
Canon clamping ring / threaded adapter ring filter adapter 60 mm | eBay
Nodal Ninja F6402-1 V2 Lens Ring Clamp for Sigma 15mm F6402-1