What simple Mac app are you currently missing?

Only Mac, not cross platform.

Do Not Disturb Manager

An app that can control which notifications are allowed when Do Not Disturb is turned on. Preferably configurable with a regex, not just per app.

Isn't that done through System Preferences > Notifications excluding the regex part?

You can disable them altogether forever and I don't want that.

Something that I am currently feeling the need to build myself:
- Reminds me to drink water + measure my daily intake
- Reminds me to take my pills (I often forget how many doses I have taken today)
- Reminds me to take my eyes off from screen

A good code snippets manager. I'd love an app similar to Codepen.