additions to the standard grc.conf (check the appropriate conf files for each command)

conf.hexdump

# offset
regexp=([0-9a-fA-F]{1,7})+
colours=bold red
count=once
======
# Hex Bytes %_p
regexp=\|.+?\|
colours=cyan
count=once
======
# Hex bytes
regexp=([0-9a-fA-F]{1,2 })+
colours=green
======
# everything in brakets
regexp=\b00 
colours=bold black

conf.nmap

# ip number                                                                                                                                
regexp=\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}
colours=bold yellow
======
# list header
regexp=(PORT|STATE|SERVICE|REASON|VERSION)
colours=bold white
======
# open
regexp=open
colours=dark green
======
# filtered
regexp=filtered
colours=dark yellow
======
# closed
regexp=closed
colours= dark red
======
# tcp n udp
regexp=(/tcp|/udp)
colours=bold black
======
# device type
regexp=(Device type:)
colours=cyan
======
# running
regexp=(Running:|Running)
colours=cyan
======
# os details
regexp=(OS details:)
colours=cyan
======
# MAC
regexp=(MAC Address:)
colours=cyan
======
# network distance
regexp=(Network Distance:)
colours=cyan
======
# Service Info
regexp=(Service Info:)
colours=cyan
======
# Agressive
regexp=(Aggressive OS guesses:)
colours=cyan
======
# no exact match
regexp=(No exact OS matches for host)
colours=magenta     

conf.ps

# darken root's processes
regexp=^root .*$
colours=bold black
=======
# everything in brakets
regexp=\[.+?\]
colours=cyan
count=more

grc.conf

# nmap command
(^|[/\w\.]+/)nmap\s?
conf.nmap

# hexdump
(^|[/\w\.]+/)ps\s?
conf.hexdump

Hi!
Have you considered contributing your confs to grc?

Particularly the conf.nmap

Nevermind, I see grc has a conf.nmap, sorry for the noise.