Loricifera, Pogonophora, Brachiopoda, Placozoa and so on.    From Wordnik.com.  [SNAIL'S TALES] Reference

Instead, I will list a compilation of some of the phyla of which I have yet to see a live member: Acanthocephala, Chaetognatha, Gnathostomulida, Hemichordata, Nematomorpha, Nemertea, Onychophora, Priapulida, Sipuncula, Echiura, Phoronida, Loricifera, Pogonophora, Brachiopoda, Placozoa and so on.    From Wordnik.com.  [So many phyla so little time] Reference