The knot tabulations do something like this. First they generate all planar 4-valent graphs (with a given number of vertices). Then they replace each vertex with an over and an under crossing. This set contains all link diagrams with the given number of crossings. Then what you do next depends on what you are interested in.

http://pzacad.pitzer.edu/~jhoste/HosteWebPages/downloads/Enumeration.pdf

The procedure for generating planar 4-valent graphs is I think the type of procedure you are asking for. It is implemented in <a href="http://cs.anu.edu.au/~bdm/nauty/">nauty</a>