Malwarebytes - Malwarebytes protects you against malware, ransomware, and other advanced online threats that have made antivirus obsolete and ineffective. Free Anti-Malware & Malware .
Clam Xav (desktop) - Specifically with Clam Xav Sentry configured to scan inserted disks.Please read global comments on this question for an explanation of why desktop apps are being recommended for virus detection on ios devices.
Avira - Cloud based email security solution
CleanMyMac X - Clean, protect and speed up your Mac
Microsoft Security Essentials - Microsoft Security Essentials is Microsoft's own foray into the world of virus protection.
Ad-Aware Free Antivirus+ - Ad-Aware Free Antivirus+ is a world’s most leading security solution that gives you comprehensive malware protection with real-time monitoring, threats alerts and automatic updates you can rest easy knowing that you are protected.