Spiked Collars! Everyone wants them. They were sent out as the second member gift, I think it was July 2010 or 2011. I can't remember, I was a non-member back then XD
Founder's Hat. These are very rare, although 1 isn't worth the least-rarest beard.
Beards! Extremely rare, but the black beard with red tip isn't that good. You can trade 2 long collars and 2 betas such as a porch swing and a beta television. The orange beard is the rarest. There are only two people in the game who own it: Infinitymagicheroisback and VisualEffects.
Spaceship Grey!!! The wallpaper is very uncommon, there are 2 people that I have seen with it. This was sold in beta for 500 gems. I had it to make it look like my den was a spaceship XD.
Mira Statue: This is a statue of the mother of Jamaa! It is worth a rhino helmet, or beta wallpaper and floor. Sorry it's so big :L
I hope this helped, and happy jamming!