1) Gamemaster Doll - the rarest doll with a history, it was given by Cipsoft to the gamemasters on 24.08.2010. It's price according to TibiaBosses pricecheck is 600-800 kk.
All Gamemasters received this doll on August 24, 2010 along with one other item of choice: Dark Trinity Mace, Solar Axe, The Epiphany, Great Shield, Ferumbras' Hat, Rainbow Shield, Snake God's Wristguard or Royal Crossbow. A few ex-Gamemasters that were still active at the time also received the doll.
2) Midnight Panther Doll - TibiaMagazine's fansite item. According to TibiaBosses pricecheck it's price is 300-350kk.
3) ...and here I have a problem, since I have no idea what's the price of original Assassin Doll, Black Knight Doll etc. I think that it's a place for one of fansite's dolls which are more rare, than for example Omniscient Owl.
If we are talking about items, which you can get in game only then top 3 looks differently:
1) Bear Doll , wchich you can get as a gift from Santa Claus.
2) Lisa's Doll , dropped by Lisa (20-30kk).
3) Vampire Doll (~3kk)
** prices may change with time!