Ostraca are, of course, potsherds. New Testament ostraca are potsherds of vessels which had once had New Testament verses written on them.
Talismans are amulets or other decorations containing small passages of scripture.
A typical talisman contained a copy of the Lord's Prayer and was worn around the neck. When Kurt Aland took over the catalog and published the Kurzgefasste Liste, he abolished the two little-used categories. In effect, the talismans and ostraca have been discarded for textual criticism.