I counted almost 25 new frameworks in this post from Patrick Balestra. I promise you there are a few you didn't realize were announced. Check them out along with all the other new iOS, Xcode, & Swift goodies. This is a really exhaustive post!
WWDC 2019 - The Things You May Have Missed by Patrick Balestra
How will all the new announcements from WWDC actually affect your development? We all know our workflow will change, but I like this post from James Dempsey about an app he has been wanting to create. He's felt overwhelmed just thinking about how to do it, but WWDC introduced three things that will make it easier. SwiftUI, Sign in with Apple, & Core Data / CloudKit interoperability all simplify development of his idea.
The Shortest Path To A Great App by James Dempsey
Here's another WWDC recap you don't want to miss. What I like about this post is Mattt reminds us that just because you haven't dug into SwiftUI, doesn't mean you're behind the curve. I haven't played with SwiftUI at all. Besides taking a look at it and understanding it, I probably won't for a while. I don't work for a company or on projects that will be iOS 13 only. I don't have to rush. He compares it to how long it took Swift to become mainstream. I waited a while on Swift as the language matured and I'm glad I did.
I guess what I'm saying is Mattt gives some great perspective. Focus on what's important to you and keep the big picture in mind.
WWDC 2019 by Mattt