Change the shape of the radial menus / icons sizes etc
Example layout 01 -my shad priest
Primary / Secondary spell watcher choices. These check for range, show cooldowns, if they've avail due to power etc.
Example layout 01 -my DK
For Moving frames / Timer locations
Example layout 01 -my lock
For linking a proc to a spell to highlight it and put a timer for the proc next to the spell.