Customize your EAGLE software with community-created programs.
Pretty much editnext-sheet/editprev-sheet, but for board layouts. Scrolls through visible copper layers based on what is used. Will work with any amount of copper layers (up to 16 of course) with no extra configuration. Top, bottom, and all also display respective place, name, docu layers as well. The ULP should be pretty easy to edit to change this behavior.