16,777,216 colors can be defined by the RGB color system, here are 256:
Color Finder - Version Two
0    1    2    3    4    5    6    7    8    9    A    B    C    D    E    F                        BACK
#FF1100 #DD1100 #BB1100 #991100 #771100 #551100 #331100 #111100
#FF3300 #DD3300 #BB3300 #993300 #773300 #553300 #333300 #113300
#FF5500 #DD5500 #BB5500 #995500 #775500 #555500 #335500 #115500
#FF7700 #DD7700 #BB7700 #997700 #777700 #557700 #337700 #117700
#FF9900 #DD9900 #BB9900 #999900 #779900 #559900 #339900 #119900
#FFBB00 #DDBB00 #BBBB00 #99BB00 #77BB00 #55BB00 #33BB00 #11BB00
#FFDD00 #DDDD00 #BBDD00 #99DD00 #77DD00 #55DD00 #33DD00 #11DD00
#FFFF00 #DDFF00 #BBFF00 #99FF00 #77FF00 #55FF00 #33FF00 #11FF00
#FFFF55 #DDFF55 #BBFF55 #99FF55 #77FF55 #55FF55 #33FF55 #11FF55
#FFDD55 #DDDD55 #BBDD55 #99DD55 #77DD55 #55DD55 #33DD55 #11DD55
#FFBB55 #DDBB55 #BBBB55 #99BB55 #77BB55 #55BB55 #33BB55 #11BB55
#FF9955 #DD9955 #BB9955 #999955 #779955 #559955 #339955 #119955
#FF7755 #DD7755 #BB7755 #997755 #777755 #557755 #337755 #117755
#FF5555 #DD5555 #BB5555 #995555 #775555 #555555 #335555 #115555
#FF3355 #DD3355 #BB3355 #993355 #773355 #553355 #333355 #113355
#FF1155 #DD1155 #BB1155 #991155 #771155 #551155 #331155 #111155
#FF11AA #DD11AA #BB11AA #9911AA #7711AA #5511AA #3311AA #1111AA
#FF33AA #DD33AA #BB33AA #9933AA #7733AA #5533AA #3333AA #1133AA
#FF55AA #DD55AA #BB55AA #9955AA #7755AA #5555AA #3355AA #1155AA
#FF77AA #DD77AA #BB77AA #9977AA #7777AA #5577AA #3377AA #1177AA
#FF99AA #DD99AA #BB99AA #9999AA #7799AA #5599AA #3399AA #1199AA
#FFBBAA #DDBBAA #BBBBAA #99BBAA #77BBAA #55BBAA #33BBAA #11BBAA
#FFDDAA #DDDDAA #BBDDAA #99DDAA #77DDAA #55DDAA #33DDAA #11DDAA
#FFFFAA #DDFFAA #BBFFAA #99FFAA #77FFAA #55FFAA #33FFAA #11FFAA
#FFFFFF #DDFFFF #BBFFFF #99FFFF #77FFFF #55FFFF #33FFFF #11FFFF
#FFDDFF #DDDDFF #BBDDFF #99DDFF #77DDFF #55DDFF #33DDFF #11DDFF
#FFBBFF #DDBBFF #BBBBFF #99BBFF #77BBFF #55BBFF #33BBFF #11BBFF
#FF99FF #DD99FF #BB99FF #9999FF #7799FF #5599FF #3399FF #1199FF
#FF77FF #DD77FF #BB77FF #9977FF #7777FF #5577FF #3377FF #1177FF
#FF55FF #DD55FF #BB55FF #9955FF #7755FF #5555FF #3355FF #1155FF
#FF33FF #DD33FF #BB33FF #9933FF #7733FF #5533FF #3333FF #1133FF
#FF11FF #DD11FF #BB11FF #9911FF #7711FF #5511FF #3311FF #1111FF