Perhaps the rarest of all the Star Wars figures (and certainly the rarest of the DROIDS line) is the intergalactic bodyguard Vlix.
Only released in Brazil under the "GLASSLITE" imprint, Vlix was the final DROIDS figure released. By some sources, Vlix was the only figure in a line of non-produced figs that were actually produced.
It is unknown how many of these are available in the secondary market.