Shapefest is one artist's (Joseph Todaro) library of ray-traced 3D renders, reportedly over 100,000 of them, all made in Cinema 4D: flat vector shapes despite the name it is not.
Real depth in one specific look: glossy, lit 3D objects, a different register from the flat or hand-drawn illustrations most of this category leans toward.
Suits presentations, hero sections, or UI mockups chasing that glassy 3D-render trend rather than flat illustration.
Free downloads cap out at 512x512px; full-resolution 3000x3000px versions need purchase or an "All Access" subscription, and recoloring means editing the rendered image, not adjusting an editable 3D file.