From https://www.developerfiles.com/location-of-startup-items-and-applications-on-mac-os-x/
Folder /Library/StartupItems
Folders:
/Library/LaunchDaemons
/System/Library/LaunchDaemons
Folders:
~/Library/LaunchAgents
/Library/LaunchAgents/
/System/Library/LaunchAgents/
crontab -l
kextstat
defaults read com.apple.loginwindow LoginHook
defaults read com.apple.loginwindow LogoutHook
/usr/libexec/PlistBuddy -c Print