These projects include a watchOS app or extension. TermiWatch draws a terminal-style watch face, Clendar is a minimal calendar with widgets, and Nightguard shows blood glucose values from a Nightscout server. Waterminder reminds you to drink water, HeartControl measures heart rate during workouts, and Chanify is a notification tool with an App Store release.
watchOS changed a lot after its first versions, and many early entries were written for WatchKit 1 or watchOS 2. Gulps, HN Reader, the Giovanni Game Boy emulator and watchOS-2-Sampler are useful history, but the list marks them as unmaintained. For a modern reference, look for SwiftUI-based watch apps and recent commits. Watch apps also need careful attention to battery, complications and syncing with the phone, so read how each project handles WatchConnectivity before borrowing code.