Graph Coloring Problems: Archive for the book "Graph Coloring Problems" by Tommy R. Jensen and Bjarne Toft (Wiley Interscience 1995), dedicated to Paul Erdös. Gives progress and new problems.
Graph Theory Open Problems: Six problems suitable for undergraduate research projects.
Open Problems in Graph Algorithms: Compiled by Jerry Spinrad.
Past Open Problems Columns: By Douglas B. West, from the SIAM Activity Group Newsletter in Discrete Mathematics.
Perfect Graphs: Conjectures and open problems, maintained at the AIM.
Perfect Problems: Unsolved problems on perfect graphs.
Problems in Graph Theory: Maintained by Peter Cameron.
Problems in Signed, Gain, and Biased Graphs: Compiled by Thomas Zaslavsky.
Problems in Topological Graph Theory: Web text by Dan Archdeacon with a list of open questions in topological graph theory.
Some Open Problems: Open problems and conjectures concerning the determination of properties of families of graphs.
Some Open Problems: Kézdy's open problems.
Three for the Money: The Degree/Diameter Problem: Students can understand and work on an unsolved problem in mathematics.
Unsolved Problems: Including the list of 50 problems of Bondy and Murty with current status. Compiled by Stephen C. Locke.