Two-dimensional plots for visual art purposes have not been explored much. Algebraic curves of more than 4 degrees are almost unexplored. One could create a program that systematically generates and plots all possible equations by degree or type, including non-algebraic ones.
Almost all ornamental elements in architecture or interior decorations are based in geometry, and most of them based on curves. Examples of curve based traditional art include: dome, arch, vault (based on arcs of circle), volutes (as scrolls on columns or violins) (based on various spirals), curlicue (based on Cornu spiral, lituus), toy Spirograph (based on roses, cycloidal curves).
Methods of artwork based on curves can include: tangents, envelope, caustics (String art); osculating circles and inversion, evolute/involute, pedal curves, parallel curves, pursuit curves.