» systemctl --type=service
UNIT                                                LOAD   ACTIVE SUB     DESCRIPTION
accounts-daemon.service                             loaded active running Accounts Service
alsa-restore.service                                loaded active exited  Save/Restore Sound Card State
avahi-daemon.service                                loaded active running Avahi mDNS/DNS-SD Stack
bluetooth.service                                   loaded active running Bluetooth service
cronie.service                                      loaded active running Periodic Command Scheduler
dbus.service                                        loaded active running D-Bus System Message Bus
kmod-static-nodes.service                           loaded active exited  Create list of required static device nodes for the current kernel
lightdm.service                                     loaded active running Light Display Manager
lm_sensors.service                                  loaded active exited  Initialize hardware monitoring sensors
ModemManager.service                                loaded active running Modem Manager
NetworkManager.service                              loaded active running Network Manager
polkit.service                                      loaded active running Authorization Manager
rtkit-daemon.service                                loaded active running RealtimeKit Scheduling Policy Service
systemd-backlight@backlight:intel_backlight.service loaded active exited  Load/Save Screen Backlight Brightness of backlight:intel_backlight
systemd-backlight@leds:dell::kbd_backlight.service  loaded active exited  Load/Save Screen Backlight Brightness of leds:dell::kbd_backlight
systemd-binfmt.service                              loaded active exited  Set Up Additional Binary Formats
systemd-journal-flush.service                       loaded active exited  Flush Journal to Persistent Storage
systemd-journald.service                            loaded active running Journal Service
systemd-logind.service                              loaded active running Login Service
systemd-modules-load.service                        loaded active exited  Load Kernel Modules
systemd-random-seed.service                         loaded active exited  Load/Save Random Seed
systemd-remount-fs.service                          loaded active exited  Remount Root and Kernel File Systems
systemd-sysctl.service                              loaded active exited  Apply Kernel Variables
systemd-timesyncd.service                           loaded active running Network Time Synchronization
systemd-tmpfiles-setup-dev.service                  loaded active exited  Create Static Device Nodes in /dev
systemd-tmpfiles-setup.service                      loaded active exited  Create Volatile Files and Directories
systemd-udev-trigger.service                        loaded active exited  udev Coldplug all Devices
systemd-udevd.service                               loaded active running udev Kernel Device Manager
systemd-update-utmp.service                         loaded active exited  Update UTMP about System Boot/Shutdown
systemd-user-sessions.service                       loaded active exited  Permit User Sessions
tlp.service                                         loaded active exited  TLP system startup/shutdown
udisks2.service                                     loaded active running Disk Manager
upower.service                                      loaded active running Daemon for power management
user@1000.service                                   loaded active running User Manager for UID 1000
wpa_supplicant.service                              loaded active running WPA supplicant

LOAD   = Reflects whether the unit definition was properly loaded.
ACTIVE = The high-level unit activation state, i.e. generalization of SUB.
SUB    = The low-level unit activation state, values depend on unit type.

35 loaded units listed. Pass --all to see loaded but inactive units, too.
To show all installed unit files use 'systemctl list-unit-files'.