The following Thompson Leaded colors will give a raku look when reduced with a flame. If you torch fire these enamels from underneath and then finish up with playing the torch over the top surface you will get an iridescence on the surface. These are colors that were tried at the Steve Artz workshop.
122 Imperial Blue
124 Medium Black
160 Lawn Green
167 Chinese Red
175 Flame Red
200 Aquamarine
234 Evergreen
241 Larkspur
290 Blue
320 Nude
334 Ivory
387 Midnight Blue
425 Flux
478 Emerald
644 Soft White
659 Turquoise
724 Gold
728 Amber
736 Chartreuse
741 Cream
755 Mikado
760 Off White
834 Smoke
839 Dark Olive
942 Gray Green
1066 Garnet