Patrick Wardle, Chief Security Researcher of R&D at Synack offers a bunch of usefull and easy to use security tools for macOS.
Here i do present the ones i find most usefull, but there is more, check it out on https://objective-see.com/products.html.
Have you ever asked yourself if the microphone and/or the webcam on your Mac is really off or if it is remote controlled by an attacker and spies on you? With Oversight you will find out whenever some software tries to access your webcam and/or microphone. More Info
Do you really know what is installed on your Mac and what is loaded when your mac starts, or when you login? Find out with KnockKnock
Do you know what modules are loaded into the Kernel of your Mac? With KextViewr you can find out
What Processes run on my Mac, what libraries they have loaded, what network connections they to have? With TaskExplorer you can find out