The current typical grades are:
#1 yellow; sometimes it is called prime yellow
#2 yellow; aka light yellow
#3 light fatty gray; which are in fact rather lighter brown
#4 fatty gray; dark brown or green
...but different manufacturers can specify only three types - #1 Yellow (Type 1), NC #2 Light (Type 3), NC #3 Dark (Type 4-Filtered), NC #3 Centrifuged (Type 4) - while others again four.
Basically, the old, impure waxes such as the 4 Medium, 5 Caupie, 6 Sandy and the 7 Fat are not in production for automotive purposes any more. Nowadays, the most impure version are just darker green, or brown but definitely not dark gray/almost black. The carnauba goes through lots of filtration steps, so we have a far superior product compared to the old times. The Japanese company Toa Kasei developed a method for extreme refining of carnauba; removing the most unstable or unnecessary particles from it. I don't know its activity in the automotive sector though.
If you compared the smell of pure(r) carnaubas or products known to contain #1 yellow carnauba, you could sniff a pleasant "background" scent which is characteristic of carnauba wax. Of course, heavily scented or oil rich carnaubas smell a lot better, but if you want to know the real smell of carnauba try an unscented or just mildly scented wax. Note: if it smells like crayons, it contains paraffin wax (which helps the ease of application).
Other important thing is that you have to watch the carnauba content in % by weight and not % by volume. Two completely different numbers.
How does Zymöl calculate? Do they refer to their final products when they give percentual figures? Just because you have to factor in that a certain % (rather low) of carnauba evaporates during cooking and cooling.
Other important waxes (with some tech talk):
Beeswax
is a glandular secretion from young worker honeybees and is used to build their honeycomb structures. The wax is harvested by removing the honey through centrifuging and melting the remaining comb. The melted wax is then filtered and molded.
Crude Montan wax
is a naturally occurring vegetable wax extracted by solvents from lignite coal deposits and peat. Refined Montan needs extra processing to remove any resins and asphalt. This hard vegetable wax has a melting point of 79-90 °C. The color ranges from dark brown to light yellow. Montan wax is highly glossy and increases water repellence and scuff resistance.
Macrocrystalline wax (paraffin wax)
is a petroleum wax made from de-oiled slack wax. Paraffin wax is brittle and has a low melting point between 46 and 71 °C. It is highly resistant to moisture. Due to its low cost, paraffin wax is frequently added to other wax blends.
Microcrystalline wax
is also a petroleum wax. Microcrystalline waxes have a crystalline structure much smaller than totally natural waxes and have a very high resistance to moisture, alcohol, acids and fingerprints.
Candelilla wax
is a natural vegetable wax found on the outer coating of the candelilla shrubs Euphorbia cerifera, Euphorbia antisyphilitica and Pedilanthus pavonis. These shrubs mainly grow in the Coahila and Chihuahuan deserts along the USA/Mexican border. The wax is extracted in the field by heating the plants in water and adding sulphuric acid. The floating wax is then skimmed and filtered.
The color of the wax ranges from yellow to tan and is slightly tacky. It is softer than carnauba, and has a melting point of 70 °C. It is sometimes used as a substitute for carnauba wax, due to its high gloss and similar hard characteristics.
Ouricury wax
is obtained from the fronds of the Brazilian feather palm (Syagros coronata). It is similar to carnauba wax in gloss and hardness, but darker in color. However, the wax is significantly more difficult to extract than carnauba, needing mechanical scraping of the fronds to release it. Ouricury wax has a melting point of 82.5 °C and is sometimes used as a replacement for carnauba, when a darker colored wax is desired (mostly woodworking).
Silicone waxes
provide a different combination of properties to that of the traditional waxes. Despite of having a low melting point, they can provide a film with increased detergent resistance and weathering abilities, especially when combined with (amino)functionalized silicones. They provide a dry film that improves dirt pick-up resistance, and retains the ease of application, spreading characteristics and shine.
A properly selected wax may reduce smear, improve film continuity (or uniformity), provide durability and promote stability by acting as a thickener. Most waxes may be described as either soft or hard wax. Hard waxes, such as carnauba and polypropylene, tend to have higher melting points, they provide a harder film finish, and promote good gloss, color intensity and durability. However, they are often more difficult to apply and buff out.
Softer waxes, such as paraffin and beeswax, tend to be better at lubricating, providing better application in terms of ease of application (rubout) and improved spreading (as I mentioned above). Soft waxes generally provide less shine. In most formulations, it is best to blend a hard wax with a soft wax to optimize their benefits.