disable gamed connections (if you don't play games) + more?

[JimLoose]

launchctl load -w /System/Library/LaunchAgents/com.apple.gamed.plist

feel free to add more services of this kind!

[TraderStf]

On the same type:

• calendarS synchronization
• ntp time
• error reporting, apple and third parties
• debug?
• geo position
• content filter

Most are leaving traces and using more ports.
e.g. NTP had (?has) security issues and used for 'malware'

But I don't know all that enough.

e.g. from nettop command in terminal just for apple dns (some are also just by IP 17...):

com.apple.content-filter
com.apple.flow-divert
com.apple.net.ipsec_control
com.apple.net.necp_control
com.apple.net.netagent
com.apple.net.utun_control
com.apple.netsrc
com.apple.network.advisory
com.apple.network.statistics
com.apple.network.tcp_ccdebug
com.apple.nke.sockwall
com.apple.packet-mangler
com.avira.fac