The rarest of the bunch. Not willing to pay the 750k-1mpp price asked in the Bazaar on my server I ran thru the instances that spawn these Family collectibles 6x before finding getting ONE of these. That's about 1 in 24, at best. Small sample size, true, but picked up 2-3 of every other one. And the players who pharm these for the Bazaar usually have a good sense of which collectibles are notably rarer than others. It's worth their while to know. On FV some of these Family collectibles sell for as low as 10k, and you see multiples of them available.
Of course, this could all be anecdotal since I doubt very many players are running thru these HA's at this point. It would be interesting to do a survey of Bazaar prices on other servers.
Edited, Oct 27th 2015 9:59am by Sippin