A set of programs such that any one of them, when given no input, prints its own code (i.e. functions like a normal quine), but when given particular inputs can generate the code of any other program in the set.

This is not to be confused with a circular sequence of programs such that any program prints out the next program in the sequence (in the case where n=2, this is a program that prints out another program, which in turn prints out the original... an example can be found here).