There is no definitive answer to this question since the rarest cue in 8 ball pool can depend on several factors, such as what country you are playing in, what type of game you are playing, and even what time of year it is. However, some players believe that the rarest cue in 8 ball pool is the Black Hole cue, which is said to be so rare that there is only a handful of them in existence. Other rare cues include the Gold Cue and the Platinum Cue, both of which are said to be very difficult to obtain.