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.