Antivirus companies other than Norton include: McAfee, Bitdefender, Avast, ESET, Kaspersky, Trend Micro, Sophos, AVG, Malwarebytes, TotalAV, and Microsoft Defender.
Norton™ is part of Gen™ - a global company with a family of consumer brands including Norton, Avast, LifeLock, Avira, AVG, ReputationDefender and CCleaner.