Library of Curves
This is a nice resource: a Famous Curves Index, provided by the School of Math and Statistics at the University of St. Andrews, Scotland.
You can view graphs of the tractrix, Fermat’s Spiral, and Quadratrix of Hippias, and see their various algebraic representations. Each entry in the Curve Index contains a brief history of the curve, some interesting facts, and links to other related curves.
This collection is similar to another fun resource provided by the same program: a comprehensive on-line library of biographies of mathematicians.