Interval Timer - Interval Timer is a mobile application that helps you stay consistent in your workouts.
Strong.app - Strenght training logger.
Tabata Timer - Tabata Timer is a mobile application that helps you perform high-intensity workouts.
wger - FLOSS workout, fitness and weight manager/tracker written with Django
Wod Blocks - A full workout timer
Bolt - Workout Tracker - Track your progress in the gym and discover new workouts with the most intuitive workout tracker for weight lifting on the App Store.