The ornamental design for a toothbrushholder, as shown and described.
FIG. 1 is a left-front perspective view of a toothbrush holder showing our new design.
FIG. 2 is a left-rear perspective view thereof.
FIG. 3 is a left side elevation view thereof.
FIG. 4 is a right side elevation view thereof.
FIG. 5 is a front elevation view thereof.
FIG. 6 is a rear elevation view thereof.
FIG. 7 is a top plan view thereof.
FIG. 8 is a bottom plan view thereof.
FIG. 9 is a right-front perspective view thereof; and,
FIG. 10 is a right-rear perspective view thereof.
The broken line showing of toothbrush holder is included for the purpose of illustrating portions of the “article” and forms no part of the claimed design.