NapBot - NapBot is Machine Learning powered sleep tracker for your Apple Watch.
F-Droid - F-Droid is an interesting alternative for Android users who want to try something different and not have to use the Goole Play store all the time.
Withings Sleep - A sleep tracking mat by Withings
APK Pure - Download apk for Android with APKPure APK downloader. NoAds, Faster apk downloads and apk file update speed. Best of all, it's free
Rise: Track Sleep & Circadian - Wake up & fall asleep better
APKMirror - Android Market and APK Downloads