Though I wrote many events for Europa Universalis IV, my own two favorite DLCs are El Dorado and Women in History. 
El Dorado has several event chains that are triggered if you send a conquistador to explore South America – they will hunt for the Seven Cities. For a full list of these events, please see https://eu4.paradoxwikis.com/Exploration_events – I took inspiration from Heinlein’s book titles when naming these events.

In-game screenshot of one of the El Dorado events, this one inspired by Sacagawea.

In-game screenshot of the final event.

Women in History

Women in History is a free DLC released on women’s international day in 2015. It contains 100 new events which I created based on actual women in history such as Caterina Sforza, Sophie Germain, and Queen Elizabeth I. For a full list of all 100 events and their text, please see Women in History events – Europa Universalis 4 Wiki.

In-game screenshot of the Queen Elizabeth I event.

In-game screenshot of the Nurbanu Sultan event.

In-game screenshot of the Isabella of Castile event.

In-game screenshot of the Kösem Sultan event.