Trying to make a good-looking app but not a designer or want a head start with ready-made UI designs? You can always try an app template. I did this a few years ago with part of one of my apps.
And here’s a modern new collection of iOS app templates written in Swift.
π AppDesignKit: Swift coded, ready-to-use, iOS app templates
They seem to be basic UIKit apps, with no SwiftUI support. They is no authentication or backend support. They run on dummy data and free sample pictures. But from a purely UI / design perspective, these templates look they have good potential. They have templates for an e-commerce app, finance, fitness, food, media, reader, social, and travel.

Via iOS Dev Weekly.