"Go from zero to hero with my comprehensive, real-world Swift tutorial projects." - Paul, Hacking with Swift
Many thanks to Paul Hudson (@twostraws) for these great courses.
Courses's material available at 
twostraws/HackingWithSwift.
This section is common for 100 Days of Swift and 100 Days of SwiftUI courses.
Here are covered the first 15 days with the basics of the Swift language.
These playgrounds are available inside the Playgrounds/ folder.
Challenges are available inside Classic/ directory.
Challenges are available inside SwiftUI/ directory.
These projects are not part of the main 100 Days of Swift/SwiftUI series, but are part of Hacking with Swift series.
Projects are available inside Extra Projects/ directory.