Best Europa Universalis IV Mods
I think this one is straightforward. The Steam Workshop has so many great mods that making a list of the best should be easier than most games.Extends the timeline from 2 to 9999, impressively representing historical border changes although the development is still biased towards Europe. The single most popular EU4 mod on the entire Workshop.
A cheat mod that can be as helpful as the Nation Designer itself sometimes.
A nation designer mod that is unique for allowing negative idea sets.
EU4 in the ancient world - extremely thorough and well-organized but also ridiculously prone to crashes.
The states and provinces of various North American and Oceanian nations mixed into the EU4 timeline.
Amazing Lord of the Rings mod that allows play even long before the events of The Hobbit.
Another nation designer mod, but unique for allowing monarch skills higher than 6.
The feel of Theatrum Orbis Terrarum is inserted into the EU4 map. There are a lot of side mods for this.
Another map mod with a lot of side mods.