Those two are the most obvious silver plays that would seem to have close-in potential. The other arena that has close-in potential is the Rare-Earth arena. There, I like GWMGF, LYSCF, ALKEF and UURAF. But they are further out in terms of return than GPL and USSIF.
There is a fifth dimension, beyond that which is known to man. It is a dimension as vast as space and as timeless as infinity.