IPv6 filtering at network edge?

I'm tightening up some network-edge filters, and in the process of testing filtering with IPv6, I found that there is a lot of ICMP link-local (fe80::) to ff02:: activity at an IX.  Is any of this necessary?  I am wary of over-filtering that cuts down functionality and doesn't increase security.  What of the IANA-reserved IPv6 addresses can be safely blocked on ingress/egress at the network edge?