ESET Mobile Security
ESET goes beyond a simple Antivirus with advanced features like protection against unwanted calls and texts, against phishing, and even against theft – the latter two features are nevertheless paid for a reasonable annual price.
ESET thus offers a free version of a powerful antivirus to scan your smartphone against threats, but also a “shield” against ransomware, a tool for scanning devices that connect to your device’s USB port (useful when you charge your smartphone on unknown sockets), or real-time protection.
All this with automatically updated virus definitions. ESET has long been a fairly respected benchmark in the industry both for the effectiveness of its antivirus software and for respecting users’ personal data.