/devmap [mapname]
- Allows you to load a map in debug mode.

/cg_drawFPS 2
- Shows you additional information, such as the number of tris / vertices / primatives / entities visible at the moment.

/cg_drawshader 1
- Shows you the texture names under your crosshairs.

/r_showportals 1
- Draws the portal boundaries, allowing you to see how the map was sectioned out.

/r_showtris 2
- Draws the outlines of surfaces. Useful for seeing how finely an area was divided.

/r_showsurfcounts 1
- Shows the number of textures in use by a particular model.

/r_showtricounts 1
- Shows the number of triangles in use by a particular model. This is a good measure of model complexity.