BUR #3635 has been approved by @Hillside_Moose.
create alias classroom_eraser -> board_eraser
create alias chalkboard_eraser -> board_eraser
Was brought up in forum #95631 6 years ago but nothing was done about it.
Second one is an utility alias since it's the likely variant people are going to search for.
EDIT: The bulk update request #3635 (forum #174038) has been approved by @Hillside_Moose.
Updated by DanbooruBot