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
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.
Mac Internet Security X9 - Intego is the industry leader for Mac antivirus, security, utility and parental controls. Products include: VirusBarrier, Mac Internet Security, Mac Premium Bundle and Family Protector.
Microsoft Security Essentials - Microsoft Security Essentials is Microsoft's own foray into the world of virus protection.
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.