Author here.
There are even more. $0 is only the current one, but you also have $1 to $4 as a history of the last ones/ I like that $_ is a reference to the last result of what you did in the console.
I documented most here:
https://docs.microsoft.com/en-us/microsoft-edge/devtools-gui...
Nice, that's great to know! Thanks for capturing them on that page. BTW I've followed you on Twitter for years. Always lots of neat tips and interesting topics -- thanks for that! :)