Spline - Design tool for 3d web experiences
Shapefest - A massive library of 3D shapes for everything!
Webflow 3D Transforms - Build 3D interactions visually, without writing any code
Wannathis - 3d illustrations and freebies
Vectary - Vectary is a free, online 3D modeling tool and sharing platform.
LostGeometry.xyz - Huge set of 91 abstract 3D objects in various styles.