Apple Watch
Fitbit Blaze
Fitbit Charge
Apple Watch Series 3
Moto 360
WHOOP Strap
Blocks
Galaxy Watch Active
HeartRate.Tech
Welltory
Cardiogram: HR Monitoring
Instant Heart Rate
Heart Rate
HeartRateMonitor
HEARTshape
Heart Watch
Apple Watch HeartRate.TechNo features have been listed yet.
HeartRate.Tech's answer:
Breathing exercises
Very nice, easy to operate. Doesn't let your finger burn from camera flash like other apps. Does quick BP readings when access to appropriate medical equipment is constrained.
Using it on my iPhone (but it has also Android version, I know) for almost 1 year. In my experience, this app is quite accurate. I tested it with my beurer pulseoximeter while struggling with covid and measurements were just like the same, so I was impressed.
Fitbit Blaze - Fitbit Blaze is a smartwatch that includes both a heart rate monitor and a fitness activity tracker. It comes with a color touchscreen, and you can change both the watch's strap and frame. Read more about Fitbit Blaze.
Welltory - Manage your energy, not your time. Improve your focus & performance with small changes in your lifestyle. Quantified self dashboard for hardworkers.
Fitbit Charge - Activity and sleep tracking wristband
Cardiogram: HR Monitoring - Accurately measure and monitor your heart rate over the whole day.
Apple Watch Series 3 - Apple's newest internet-connected smartwatch
Instant Heart Rate - The first, fastest, and most accurate mobile heart rate monitor.