Fitbit has everything I need, the steps, the Heart Rate, it has all of my exercising modes, and it has a fair price. It has a rather simplistic User interface, which I really like to be honest. Highly recommened!
Lose it! - Snap a photo of your food to get nutritional facts
SmartHealth - SmartHealth is a health and fitness app that effectively monitors and records your sleep patterns and various health-related parameters such as heart rate, blood pressure, etc.
Strava - The #1 app for runners and cyclists
Fitness Coach: Home Workout - Fitness Coach: Home Workout is an interesting app that offers you customized workout programs that are easily integrated with your hectic routines.
Workouts by Muscle Booster - Workouts by Muscle Booster is an app that provides you the home as well as gym workout plans.
HryFine - HryFine is an app that can integrate with various wearable smart products like smartwatches, bracelets, and bands and informs you about phone calls, messages, emails, etc.