For when your shitty laptop – which kept overheating under Windows and is now a server but with a totally borked BIOS (yes, I’m looking at YOU HP – what da fuck?) doesn’t have Wake On Lan:
# Install ethtool on the 'server'
sudo apt install ethtool
# keep it listening
sudo ethtool enp3s0
# Find it's MAC Address e.g. 00:1a:2b:3c:4d:5e
ip a
# put it to sleep
sudo systemctl suspend
# send a 'magic packet' from another machine on the LAN
wakeonlan 00:1a:2b:3c:4d:5e