Listed below are my favourite health apps for all sorts of health related things…

Insight Timer
Thousands of FREE guided meditations (select by time and topic), music tracks and ambient sounds, podcasts, talks, discussion groups and community features to calm the mind, focus, sleep better and relax, editable meditation timer, stats and milestones for tracking your progress, integration with Apple Health Mindful Minutes.
 
Omvana 
Guided meditations (FREE and PAID options) for all aspects of your life, variety of meditation experts, background music mixer to personalise your meditation practice, HealthKit integration that recognises your stress level and helps you keep calm.
 
Headspace App 
Learn meditation and mindfulness in just 10 minutes a day. If you enjoy ‘Take10’ (10 days free) and want to learn more, you can choose to continue and get access to hundreds of hours of original meditations as you subscribe. These include guided and unguided lessons and range from 2 to 60 minutes long. Subscriptions available.
 
Zen Mixer App 
User-friendly interface, wide range of meditation tracks, relaxation exercises and guided sessions. Free introductory meditation sessions available, sampling the basics of meditation and help with getting into the habit of meditating regularly. Timers and alarms to remind yourself not to get too caught up in the rush. Subscriptions available.
 
Calm App 
10-minute programs added daily to help ease you into the day or unwind before bed, adult bedtime stories, 7 and 21day programs for beginners and advanced users, new Calm Masterclass every month, breathing exercises for relaxation, exclusive music engineered to help you focus, relax or sleep, 30+ soothing nature sounds and scenes to use during meditation, yoga or to help you sleep. Subscriptions available  
 
The Mindfulness App ($1.99)
The Mindfulness App can be used by everyone. It is easy to use and you can choose between different types of guided meditations, meditation in silence, guided introductions, and for how long you want to sit.
 
The Monash University Low Foodmaps Diet App ($9.99) 
The FOODMAPS diet developed by researchers at Monash University works by restricting foods high in some carbohydrates called FODMAPs, which can be hard to digest, causing gastrointestinal discomfort. This app helps you with the list of foods you can and cannot eat, recipes and shopping lists.
 
f.Lux App (Free) 
Looking at the computer screen at night time may send the wrong message to your brain and keep you awake. To avoid that and keep your circadian rhythm right you can download this app that makes the color of your computer display adapt to the time of the day, warm at night and like sunlight during the day. available from https://justgetflux.com
 
Sleep time App (Free) 
Smart alarm clock that analyses your sleep and wakes you up at the perfect moment of your lightest sleep phase. Wake up feeling refreshed.
 
iPregnant Pregnancy Tracker (Free)
This pregnancy tracker records and tracks each prenatal appointment, features journal, week information, reminders, photos, community forum and many other useful tools

Clue period tracker

Easy to use.  Options for adding exercise, mood, stool, intercourse etc.  Predicts when your next period is due.