Consiglio: If you lost your phone, call it from a number you HAVEN’T in your contacts. If somebody wants to return it to you they are actually able to reach out to that person.

I recently tried to return a lost phone to its owner. I charged it over night and woke up to several missed calls on it. But since it was locked I could only access the lockscreen that said over and over: missed call from David, 2 missed calls from Michael etc. There was even a message: 'hey if you fond this phone, please call me!' But obviously I couldn't because it was from a known contact and it only displayed the name!
If only the person had called from a unknown number I could've returned the phone much earlier!