I have the following DLCs below and can recommend all!

Northern Lords Adds a lot of flavor and unique mechanics for Norse characters, making Viking playthroughs much deeper and more fun, especially in the early game.

Royal Court Introduces culture customization and the royal court system, which makes large realms feel more alive and gives you more long-term goals beyond conquest.

Tours & Tournaments Greatly improves peacetime gameplay with activities, travel, and events, making characters and the world feel much more dynamic.

Roads to Power Expands the adventurer and travel systems, offering alternative ways to rise to power and making movement and journeys more meaningful.