I claim the ornamental design for a cell phone stand holder, as shown and described.
FIG. 1 is a Perspective view of a cell phone stand holder showing my new design;
FIG. 2 is a Front view thereof;
FIG. 3 is a Back view thereof;
FIG. 4 is a Left-side view thereof;
FIG. 5 is a Right-side view thereof;
FIG. 6 is a Top view thereof; and
FIG. 7 is a Bottom view thereof;
FIG. 8 is other perspective view of a cell phone stand holder showing with tablet; and,
FIG. 9 is another perspective view of a cell phone stand holder showing with cell phone.
The broken lines in FIG. 8 and FIG. 9 depicting a tablet and a cell phone illustrate environmental subject matter and form no part of the claimed design.