In 2021, Fiat offered a range of models across different global markets. While this list may not be exhaustive and availability could vary depending on the specific region, some of the most popular Fiat models in 2021 included:

1. Fiat 500: A compact city car available in multiple versions, including the 500, 500C (convertible), and performance-oriented Abarth models. The all-new, all-electric Fiat 500e, which was introduced in 2020, was also available.
2. Fiat 500L: A larger, more versatile version of the Fiat 500, designed for families and offering more space and practicality.
3. Fiat 500X: A compact crossover SUV based on the Fiat 500, offering more ground clearance and available with all-wheel drive.
4. Fiat Panda: A small, practical hatchback known for its versatile interior and economical engines, available in regular and 4x4 versions. The mild hybrid version, called the Panda Hybrid, was also available in 2021.
5. Fiat Tipo: A compact sedan, hatchback, and station wagon, the Tipo replaced the Bravo in Fiat's lineup and offered a spacious and affordable alternative in the compact segment. In 2021, the Tipo received a facelift with updated styling and features.
6. Fiat Argo: A compact hatchback for the South American market, replacing the Punto in this region.
7. Fiat Cronos: A compact sedan for the South American market, based on the Argo hatchback and replacing the Linea in this region.
8. Fiat Doblo: A panel van and leisure activity vehicle available in cargo and passenger versions, offering a spacious and versatile interior.
9. Fiat Fiorino: A small commercial vehicle, available as a cargo van or passenger-oriented "Qubo" model.
10. Fiat Ducato: A large commercial van available in various sizes and configurations, often used for camper conversions.
11. Fiat Mobi: A compact city car for the South American market, offering a more affordable and compact alternative to the Fiat Uno.
12. Fiat Strada: A small pickup truck primarily sold in South American markets, featuring a unibody construction and a versatile cargo bed.
13. Fiat E-Ducato: An all-electric version of the popular Ducato commercial van, introduced in 2021, offering zero-emissions driving and a variety of configurations.

Please note that not all of these models were available in every market, and some had different names or specifications depending on the region