Unifier
Keep your people close. Sort the ones who matter into arcs (family, friends, work...) and log a contact in a tap. The orbit puts you at the centre and everyone else at the distance they've drifted, so the person you haven't spoken to in months is impossible to miss.
Like every app here, it installs straight from your browser. Open it on mobile and add it to your home screen to use it as an app.