The ornamental design for an expansionbase for notebooks, as shown and described.
FIG. 1 is a front perspective view of an expansion base for notebooks showing my new design, wherein the expansion base is integrated with speaker and heat-dissipating functions;
FIG. 2 is a rear perspective view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a rear view thereof;
FIG. 5 is a top view thereof;
FIG. 6 is a bottom view thereof; and
FIG. 7 is a right view thereof, wherein a left view thereof is a mirror image of the right view; and,
FIG. 8 is an operational perspective view thereof, showing a notebook placed on the expansion base for notebooks.
Broken lines shown in the drawings illustrate portions of the expansion base and a notebook computer, and form no part of the claimed design.