Aaron,
The short answer is none. I’ve been using Macs since 1989 (System 6) and I have never used any kind of security software and have never had any problems.
However, there are different points of view:
https://www.macworld.co.uk/feature/m...ruses-3454926/
Having read the article, I haven’t changed my opinion. The key is to be very careful with what you load on your computer, particularly email attachments.
Rather than spend money on anti-virus software, I would spend it on a password manager (1Password) and a good VPN (NordVPN). That would buy you much more security.