ClamAV is not a good example. Being an open-source volunteer-maintained thing that started as being specifically for scanning email it has a terrible detection

ClamAV is not a good example. Being an open-source volunteer-maintained thing that started as being specifically for scanning email it has a terrible detection rate at finding general windows malware compared to commercial products. Anecdotally, based on uploading exe's that I come across to virustotal, ClamAV detects 10% of malware that the well known AV packages alert on.