RetroHexChat supports the standard 16-color IRC palette for both foreground and background text.
Using Colors
Press Ctrl+Shift+D or click the цвет button in the formatting toolbar, then select a color from the 4×4 picker grid.
Color Palette
0 White 8 Yellow 1 Black 9 Light Green 2 Navy 10 Teal 3 Green 11 Cyan 4 Red 12 Blue 5 Maroon 13 Magenta 6 Purple 14 Grey 7 Orange 15 Light Grey