Apps related to “who calls”
Anti-spam: Kaspersky Who Calls
World History Offline
imo video calls and chat
JioCall
Who is calling? Voice Notify
Who's Who
Announce Who Is Calling
Call Recorder
LINE: Free Calls & Messages
BBM - Free Calls & Messages
imo beta -video calls and chat
هدهد
TCaller - phone identificatory, who called. 
Who Invented Who
Guess Who
Cadpage
Who am I? (Biblical)