Neighbor Discovery (IPv6)

Neighbor Discovery is a feature of IPv6 allowing you to discover hosts by sending a message to the multicast address of a local subnet.

IPv6 Address Purpose
ff02::1 Multicast address for all link-local IPv6 nodes
ff02::2 Multicast address for all link-local IPv6 routers

Linux

Simply use the native ping and ip commands.

ping -6 -I <INTERFACE> ff02::1
ping -6 -I <INTERFACE> ff02::2
ip neigh

Nmap

Use the targets-ipv6-multicast-echo NSE script.