Throughout Sichuan cuisine, there are a handful of herbs and spices that you'll find repeatedly in recipes, and several stand out as "The Five Fragrances" that are used to make "5 spice powder": fennel, pepper, aniseed, cinnamon, and clove (in addition to chilli peppers, chilli powder and Sichuan peppercorn, of course).
Fennel is highly aromatic and adds layers of flavour when used in cooking. Traditionally it's been an herb used in Italian sausages and Indian cuisine, but fennel seed is actually one of the spices used to make what we known now as "5 spice powder." It's also known as one of the main ingredients of absinthe.
Oddly, Chinese cuisine prefers to use White Pepper over the traditional Black Pepper. It is often milder and less complex in flavour. Both peppers are picked from the same plant but are treated differently after being picked to vary their flavours and complexities.
Much like Fennel, Aniseed (not to be confused with Star Anise) is also a prime ingredient in making absinthe. It offers a mixture of flavours combining cumin, honey, cardamom, and liquorice. Additionally, this spice is high in fibre, calcium, and potassium. Star Anise is usually included in dishes that must be slow-cooked and has a distinctively liquorice-based taste. It's now very popular to include in not just Chinese cuisine, but also adds dimension to cocktails nowadays.
We are all familiar with the health benefits and taste of cinnamon, but there are some Sichuan recipes that call for Cassia Bark, which is essentially a stronger form of cinnamon. It's often used to add on a layer of bitterness to dishes and complements Sichuan peppers. When cinnamon is used in lieu of Cassia Bark, the chef must be aware of the sweetness in the dish, as cinnamon's level of bitterness is considerably lower.
Cloves are often used in both Asian and Western cooking, and gives off a strong yet sweet aroma to certain dishes. They hold an essential oil called 'eugenol', which often gives off a bitter, numbing flavour.
Sichuan people believe that eating hot food in the summer helps to cool down the body, while eating it in the winter helps to bring a certain amount of heat into your body to keep it warm. The Chilli Peppers that are used in cooking Sichuan food are the main source of said heat, and you'll find them in an arrangement of dishes at Chilli Fagara.
It may be called a peppercorn, but this spice is actually a dried red berry that puts out 'hydroxy-alpha sanshool', which gives off an all-too-familiar numbing and tingling effects when we eat Sichuan cuisine.
Sources: https://www.sbs.com.au/food/article/2019/01/01/7-key-flavours-sichuan-cuisine https://thewoksoflife.com/chinese-spices-condiments/#cloves https://www.thespruceeats.com/about-white-pepper-694250