For the normal bricks; a nice chart with sizes and some pricing.
The funky stuff is the custom cast or extruded brick like the warm morning corner vented brick.
The Newcastle stoves have a brick cast from refractory and are not standard brick sizes.
There are metal forms that bolt together and the refractory is poured in then poped out when dry.
You can cast it in place also, just make sure your form will not leak much!
Cardboard and some bracing, then start a small fire to cure and burn out the form!
You milage may vary, there are many ways to skin this cat!