The ornamental design for a two-piece placard holder magnetically attached, as shown and described.
FIG. 1 is an exploded front perspective view of a two-piece placard holder magnetically attached showing my new design, the broken-line disclosure of the placard and rearview mirror is for illustrative purposes only and forms no part of the claimed design;
FIG. 2 is an alternate exploded front perspective view thereof,
FIG. 3 is a front perspective view of the two pieces attached,