Malwarebytes - Malwarebytes protects you against malware, ransomware, and other advanced online threats that have made antivirus obsolete and ineffective. Free Anti-Malware & Malware .
Avira - Cloud based email security solution
Panda Antivirus for Mac - A bare bones malware and anti-virus scanner.
Easy PC Optimizer - Easy PC Optimizer is an easy and quite simple tool for enhancing the performance and boosting up the speed of the system.
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.
Microsoft Security Essentials - Microsoft Security Essentials is Microsoft's own foray into the world of virus protection.