Think of it as this..
if it can search for a lv. x[excluding premier ball].. it can get a LEGEND Piece.
Only addition is Luxury Ball can get a LEGEND too.
If you wanna know what pokemon can, then I can let you know.
Cards that do not search for a specific stage of Pokemon can search for a Legend Piece. Examples are Luxury Ball, Pokemon Communication, and Bebe's Search.
Roseanne's and Elm's CANNOT search for Legend Pieces.
