Wake-on-LAN quit working with latest kernel (Bionic)
To make this persistent I created a script in /etc/network/if-up.d
#!/bin/sh
/sbin/ethtool -s [card] wol g
This re-enables WoL every boot.
It seems that Wol is disabled by default in the r8169 module for now, and now we must use userspace tools like ethtool to get it: #1752772 and r8169 ethernet card don't work after returning from suspension. See also Wake-on-lan Ubuntu support on getting Wake-on-lan persistent on boot. Or just use nm-connection-editor in Network-manager for that.