Is there any documentation regarding "wake-on-LAN" or "magic packets"
for IPv6-only networks?

Issues in low power mode are as follows:

Assume in low power mode, the network adapter only responds to wake on
LAN/magic packets and no other traffic.

If using IPv6 and unicast, Neighbor Cache aging is an issue because in
low power mode the node will not respond to Neighbor Solicitations; as
a result,
the node is removed from its router's Neighbor Cache.

If using IPv6 and multicast, responding to General and Multicast-
Address-Specific queries is an issue because in low power mode the
node will not respond to queries with Reports.

The implication of the above two scenarios is that the router will
drop all packets for destination addresses it does not recognize
whether it is a unicast or multicast address. (Assume destination is
node behind router.)

This problem is solved in IPv4-only networks by using a technique
called Subnet Directed Broadcasting which is not possible in an IPv6-
only environment.

See http://www.amd.com/us-en/assets/cont...docs/20213.pdf