What is the consensus on how many AV tools should be incorporated into the network?

Good question, but to answer it we need to break it down further. 

Are you asking how many vendors, how many tools, or how many layers of protection that you need to deliver a proper AV solution?

If you’re in a position where you’re thinking of just implementing something like Defender for endpoints, then you’re doing something well. However you need to not just look at defending this edge, but instead take a look at defence in depth. Consider the overall strategy of your architecture to identify the gaps and potential breaches. 

For some orgs, one AV solution is fine. For others, they may need 3. 

If you can answer the questions above, then we’ll be able to expand further. Otherwise, send me a direct message and let’s talk :) 

Can you add a little more context? Typically, you will find 3 advanced malware/AV solutions in most normal infrastructures. 
Endpoints
Network Edge (FW,IPS)
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