Is there an app to select who's going to make my phone ring? I usually sleep with my cellphone on silent mode, but some important people are allowed to wake me up whenever they want. When it's not on silent mode, some inconvenient people usually wake me up for nothing. Is there a way to make a call filter and allow only these important  people to make my phone ring?
I recommend Sanity which is free and open source. It has many calling-related features, such as call filtering by caller name, that you can set it to get silent when some people call you.

These two features, copied from description of the app, would really help you:

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block unwanted calls and SMS: automatically refuse incoming calls and SMS filtering out the phone number (include or exclude anonymous and/or unknown numbers, favourites, contacts and groups; enable the block by choosing date and time); advanced: choose between different block methods to confuse the caller!
urgent calls: choose what phone numbers your phone will ring or vibrate also when it's in silent mode.


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