FIG. 1 is a perspective view of an embodiment of the ornamental design of a substrate holder.
FIG. 2 is a rear view of an embodiment of the ornamental design of a substrate holder.
FIG. 3 is a front view of an embodiment of the ornamental design of a substrate holder.
FIG. 4 is a right side view of an embodiment of the ornamental design of a substrate holder.
FIG. 5 is a left view of an embodiment of the ornamental design of a substrate holder.
FIG. 6 is a top view of an embodiment of the ornamental design of a substrate holder.
FIG. 7 is a bottom view of an embodiment of the ornamental design of a substrate holder.
FIG. 8 is a perspective view of second embodiment of the ornamental design of a substrate holder.
FIG. 9 is a rear view of second embodiment of the ornamental design of a substrate holder.
FIG. 10 is a front view of second embodiment of the ornamental design of a substrate holder.
FIG. 11 is a left side view of second embodiment of the ornamental design of a substrate holder.
FIG. 12 is a right view of second embodiment of the ornamental design of a substrate holder.
FIG. 13 is a top view of second embodiment of the ornamental design of a substrate holder; and,
FIG. 14 is a bottom view of second embodiment of the ornamental design of a substrate holder.