The ornamental design for a gamenetbase, as shown and described.
FIG. 1 is a side view of a game net base showing the new design in an environment of use;
FIG. 2 is a perspective view of a game net base shown in an environment of use;
FIG. 3 is a perspective view thereof shown without its environment of use;
FIG. 4 is a left-side view thereof, the right-side view being a mirror image thereof;
FIG. 5 is a front view thereof;
FIG. 6 is a back view thereof;
FIG. 7 is a top view of the game net base shown in FIG. 1; and,
FIG. 8 is a bottom view of the game net base shown in FIG. 1.
The broken line showing of the support arms and net in FIGS. 1-2 depict environmental subject matter and form no part of the claimed design. All other broken lines depict portions of the game net base that form no part of the claimed design.