Here is the full list of all 38 Cities: Skylines II achievements.
Unlock each building available in the base game.
Reach a population of 100,000.
Have 20 active transport lines. These can be passenger or cargo lines or any mix of the two.
Build any airport.
Unlock 150 map tiles in a single city.
Have 5 city policies active simultaneously.
Create 10 different districts in a single city and assign policies to each.
Follow a citizen's lifepath from childhood to old age.
Use the editor to make a map.
Reach milestone 20.
Have 50 active transport lines. These can be passenger or cargo lines or any mix of the two.
Have at least 1000 citizens and an average happiness rating of 25%.
Build 10 signature buildings in a single city.
Use the editor to make an asset of any other type than map.
Have at least 1000 citizens and a city attractiveness rating of 90.
Build a city where at least 20% of the population has a university level of education.
Build 10 parks in a single city.
Bulldoze a total of 1000 buildings.
Have 6,000 citizens treated at medical clinics or hospitals in a single city.
Have a total of 10,000 tourist visits in a single city.
Build all unique city service buildings in a single city.
Have a look at each individual info view panel.
Experience a hailstorm.
Experience a tornado.
Experience a forest fire.
Have a city that produces electricity by only using renewable energy sources.
Build 5 signature buildings in a single city.
Unlock 50 map tiles in a single city.
Experience all four seasons by building a city in a climate with a snowy winter.
Use the photo mode to take a screenshot.
Have a total loan of at least 200,000 in a single city.
Assign a policy to a city district.
Have at least 1000 citizens and an average happiness rating of 75%.
Create a city district and assign a city service to that district.
Reach enough milestones to unlock all city services in a single city.
Have buildings from all four zone types in a single city.
Plant 100 trees or bushes with the landscaping tool in a single city.
Build city with residential, commercial and industrial zones, water, and electricity.