Wolfram Research
Wolfram Math World: Graphs
MathWorld.com shows many types of discrete math graphs and provides links to related topics.
Oregon State University
Oregon State University: Rational Functions
A look at graphs of rational expressions, finding properties of the graph by using calculus. Formulas included.
Curated OER
Graphs: Online Calculator
This resource presents an online calculator which allows you to graph rational functions. Requires Java plug-in.