The ultimate in highlighting local variation is something like the Glasbey colourmap:

https://imagej.net/Glasbey

https://www.bioss.ac.uk/people/chris/colorpaper.pdf

EDIT the "hue ramps" style of colormap is also quite interesting, although i can't find an example, and can't be bothered to create one:

http://soliton.vm.bytemark.co.uk/pub/cpt-city/imagej/tn/hue_...