To check all running services
service --status-all | grep '\[ + \]'
To check all services (running & non running)
service --status-all

#To show all installed unit files use:
systemctl list-unit-files
#To show all Ubuntu services:
systemctl --no-pager
#To show all unit files:
systemctl list-units --all --type=service --no-pager
#To show systemd unit files:
systemctl list-unit-files --no-pager
#To show enabled systemd service unit files:
systemctl list-unit-files | grep enabled
#To show disabled systemd service unit files:
systemctl list-unit-files | grep disabled