Here's extended classification of gas giants from Encyclopedia Galactica:
1. Cryoazurian: 0-90 Kelvin. No tropospheric clouds and only faint hazes. Dull blue in color, occasionally with hints of cyan from hydrocarbon hazes in the upper atmosphere.
2. Frigidian: 5-20 Kelvin. Extremely cold hydrogen clouds only capable of forming on worlds that are far from any stars. White clouds with hints of grey and blue.
3. Neonean: 15-35 Kelvin. Very cold neon clouds.
4. Borean: 35-60 Kelvin. Clouds of nitrogen, carbon monoxide, or more rarely oxygen. Various colors, typically pale pink or purple, although reds, oranges, or browns may occur from discoloration from organic hazes.
5. Methanean: 60-90 Kelvin. Clouds of methane, ethane, and occasionally argon. Usually accompanied by moderate amounts of organic haze. Light blue to turquoise in color, but can become more of a dull green or even bronze from extensive haze.
6. Mesoazurian: 90-550 Kelvin. Uncommon clarified atmospheres. Usually teal or green in color as a result of heavy discoloring by organic and sulfur hazes.
7. Tholian: 60-550 Kelvin. Various organic hazes that obstruct the surface and any clouds below. Various colors, but usually pale yellow, orange or brown.
8. Sulfanian: 80-180 Kelvin. Sulfur enriched ammonian worlds. Clouds of hydrogen sulfide and ammonium hydrosulfide, with lesser amounts of ammonia, hydrogen chloride, sulfur dioxide, and organic hazes. Dull yellow, orange, or gold in color.
9. Ammonian: 80-190 Kelvin. Clouds of ammonia, ammonium hydrosulfide, and occasionally carbon dioxide, with significant organic haze. Various colors, typically cream, peach, or orange.
10. Hydronian: 170-350 Kelvin. Water clouds, usually with some amount of organic hazes. Clouds are predominantly white, but can take on a yellow or brown tinge from hazes.
11. Acidian: 250-500 Kelvin. Clouds predominantly of sulfuric acid, with significant amounts of sulfur aerosols. Phosphoric acid and ammonium chloride clouds can occur but more rarely. Tan, taupe, or beige in color.
12. Pyroazurian: 550-1300 Kelvin. Very few clouds or hazes, especially above 900 K. Various shades of blue depending on the amount of haze.
13. Sulfolian: 400-1000 Kelvin. Hazes of sulfur and organosulfur compounds. Most often gold or bronze in color, but can take on more extreme green or orange hues as well.
14. Aithalian: 550-1000 Kelvin. Haze that consists of soot, hydrocarbons, and occasionally silicones. Typically a dull brown, but can also be dark shades of grey, hazel, or olive.
15. Alkalinean: 700-850 Kelvin. Clouds of alkali chlorides, primarily potassium chloride. Often covered by Aithalian haze, making them somewhat rare. Usually bronze or greenish-brown in color.
16. Hyperpyroazurian: 1300+ Kelvin. No visible cloud deck, and only slightly hazy. Silicate cirrus clouds may be present on cooler worlds. Daysides are various shades of blue depending on the amount of haze, with nightsides being colored according to thermal luminosity.
17. Enstatian: 1300-1900 Kelvin. Silicate clouds containing magnesium, iron, and occasionally more uncommon metals. Typically grey with a tinge of blue, green, or brown.
18. Refractian: 1800-2300 Kelvin. Clouds of refractory oxides, primarily aluminium oxide, titanium dioxide, and calcium oxide. Usually red, orange, or tan in color.
19. Carbean: 2000-2900 Kelvin. Clouds of refractory carbides such as titanium and vanadium carbide. Moderate carbon haze from dissociation of silicon carbide. Limited to carbon rich worlds. Often dark brown in color.