Malwarebytes - Malwarebytes protects you against malware, ransomware, and other advanced online threats that have made antivirus obsolete and ineffective. Free Anti-Malware & Malware .
Panda Antivirus for Mac - A bare bones malware and anti-virus scanner.
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.
Sophos Home - Business-grade cybersecurity for home users