The ornamental design for a remote controlholder, as shown and described.
FIG. 1 is a perspective view of a remote control holder showing my new design;
FIG. 2 is a front plan view corresponding to FIG. 1 (with rear plan view being a mirror image); and,
FIG. 3 is a top side plan view corresponding to FIG. 1 (with each of the right side, left side, and bottom side plan views being the same).
The broken lines showing of remotes and a logo in FIG. 1 are for the purposes of illustrating the environment of the article and the design only and form no part of the claimed design.