Came here to suggest Streaks, I've been using it for a few months now. My favorite features are:

- Streaks that track Apple Health data. Really nice job with the integration. I use this for tracking daily calorie, macronutrient, and workout goals.

- "X times per week" streaks. I take rest days from working out, so it's nice to have an abstraction that doesn't treat them as failures or breaking the streak.

I guess I should go give you guys a good app store review now. Thanks for making this!