The Res Publica Add-on for Europa Universalis IV has 5 achievements.
As Poland, become an absolutist monarchy, abolishing the Sejm.
Get a ruler of your dynasty on the throne of Poland or the Commonwealth while they are an elective monarchy.
Get Orangists in power with 100% Republican Tradition, and owning a province in China.
Have a 75% Trade share in both the Alexandria and Constantinople nodes as Venice, owning less than 10 cities.
Restore the Danelaw region to Danish rule, and make it Danish culture.