What are some blue team tools in Kali Linux (Purple) that can benefit small to mid sized businesses and be implemented for no cost other than time/labor?

I am not very familiar with Kali Purple yet as I have not been able to download it on my Mac’s VM software, but from what I am seeing there are a lot of open source tools including SIEM solutions. My goal is to expand the solutions currently being offered to low to mid size businesses as a lot of CS tools are expensive and shops of this size can lack the resources to implement them.

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