I recently saw a page of artwork on the internet from X-Men 64 by Don Heck and Tom Palmer. It appeared to try and mimic the art of Neal Adams who had drawn the previous issues. I figured it would be easy to find a reprint of it, but that doesn't seem to be the case. According to the GCD it was only reprinted in The Official Marvel Index of X-Men #3, whatever that is. I assume it is in an X-Men Essential tpb.
I wonder if there is a reason for this. I think I saw that this issue introduces a new character; Sunfire or something like that.