|Art of War||1|
|Rights of Man||1|
|Wealth of Nations||2|
|Mandate of Heaven||2|
|Cradle of Civilization||2|
|Women in History||3|
Note: The tiers are based on my personal opinion and the EU4 community consensus; however, the tiers may differ from other players.
Paradox has released 14 DLCs for EU4 in the last five years, and they have become a topic of discussion in the gaming community because they are viewed as overly expensive, particularly since they significantly change some core gameplay mechanics.
Tier 1 DLCs
The Wealth of Nations
The Wealth of Nations adds a trade focus to the game and introduces privateering as a game mechanic, which is useful against your rivals. It also changes your main trade city and introduces trade companies that significantly change both expansion and trade mechanics.
Art of War
Art of War is one of the first DLCs you should buy. It adds so much to the game that it’s worth buying at full price. It adds to the war mechanic, allows you to direct your allies and subjects, transfer occupation of an occupied province, and more.
Common Sense introduces a monarch point focus, changes to HRE game mechanics, and allows you to increase the province development using monarch points. It also adds changes to religion, governments, and new subject interactions.
The Cossacks focus on hordes and introduces the trust and favor system that streamlines diplomacy and warfare. It also adds new espionage actions, fleet improvements, and more.
Dharma changes some key game mechanics, adding more depth to many aspects of the game, including the trade mechanics, government system, policy system, and new missions to Indian nations.
Tier 2 DLCs
El Dorado offers new features to colonization and playing in the new world, including new religions, the nation designer, and the custom nation feature.
Rights of Man
Rights of Man has some minor religious changes, introduces the great power mechanic, and adds consorts, so you don’t have to suffer from Regency for years.
Mandate of Heaven
Mandate of Heaven adds new mechanics, such as the mandate, Imperial reforms, and tributaries. It also gives access to manchu banners, changes to Japan, and new diplomatic macro builders.
Conquest of Paradise
Conquest of Paradise adds new mechanics to the North American tribes.
Res Publica adds new mechanics for republics, Dutch republics, and merchants republics.
Mare Nostrum adds new mechanics for raiding coast as Barbary nations and condottieri, allowing nations to hire other nations armies.
Third Rome focuses on the Russian region and introduces new Russian government types.
Cradle of Civilization
Cradle of Civilization focuses on the Middle East and features new mechanics for Muslim nations.
In conclusion, Tier 1 DLCs change the game mechanics significantly, Tier 2 DLCs add more flavor to the game, and Regional DLCs are useful if you want to play in that particular region.
As a beginner, it’s best to prioritize Tier 1 DLCs, but as you become more experienced and want to add more flavor to the game, you can start buying Tier 2 and Regional DLCs.