My favourites among the listings are a series of molds for The Final Frontier figurines produced by Galoob. These were made by roto-molding, which Prop Store have an excellent description of in their auction catalogue:
Rotational molding or “roto-molding” uses liquid vinyl material to create items such as baby doll heads or squeeze toys. The molds are composed of one piece with an opening. A set amount of vinyl is poured into the opening, which is then capped and rotated in many directions while heated until the material forms an even, detailed coat on the inside of the mold. While still warm, the part is pulled from the mold and allowed to cool. Roto-molding is a very economical manufacturing method because the mold is cheap to produce and simple to use.All five character's in Galoob's Final Frontier range are available, Klaa, Sybok, Kirk, Spock, and McCoy, although most of the molds are missing parts, with just Klag and McCoy complete (I wonder if you could make your own figures from them?)
The molds themselves are made by submerging a wax pattern in a bath and electroplating onto it until the desired mold thickness is reached. The wax is then melted out of the mold, leaving the “clean” form inside. The inside of the mold is where the detailing lies; therefore, the exterior may only provide a marginal representation of the final toy.
Also from Galoob is an prototype for a very rare unproduced TNG Romulan figure, which comes presented on a Captain Picard card-back.
Another card-back it offered on it's own, for a Tasha Yar figure. This is a pre-production print, which on the back includes promos for Star Trek walkie talkies and a radio which were not produced, and were removed from the back of the final production run of this packaging.
From Mego, Galoobs predecessor in Star Trek toys, there's a unique Star Trek Headquarters banner used at Toy Fair.
There are also several Mego figures in the auction, but unlike the other Star Trek lots, they're just collector's quality production toys, rather than anything unique. Similarly, there's a set of Danbury Mint figurines in the auction too.
There are a lot of lots from Playmates toys, who succeeded Galoob and then went to town with the biggest range of Star Trek figures ever seen. Lots include this set of seven TNG and Voyager first shot prototypes. I think the Guinan figure looks rather striking in solid red! Also included are Picard (as "Galen" from Gambit), Q, The Doctor, Tuvok, Torres, and Neelix.
Several TOS characters are offered in pairs, including a first shot prototype, and a hand-painted hardcopy. Which again Prop Store have an excellent description of:
A hardcopy is a prototype in the truest sense of the word because it is created entirely by hand during the development phase at the toy company or at a contract vendor that specializes in such work. After an action figure design is sculpted, silicone molds are made of each part and from those molds urethane castings are made. Literally the castings are a hard copy of the original wax sculpting. Typically the joints are created by sanding and drilling the mating surfaces and steel dowel pins are inserted to connect the parts. The figures are expertly painted by hand and used for promotional photography, show samples, commercial shoots, or as paint masters to guide the production factory on the desired deco scheme. Specific unpainted hardcopies are used to create the steel production molds, although most unpainted hardcopies are simply spares.Offered are Uhura, Sulu, Scotty, Spock, and Kirk:
An interesting feature of hardcopies is that they are slightly larger than the production action figure due to shrinkage in the plastic injection molding process. Because of the handmade nature of hardcopies they are created in very limited quantities with generally under a dozen of each created and sometimes far fewer.
A further series of hardcopies are available for TNG figures. These aren't paired up with other prototypes, but do include more of the accessories each figure came with. Offered are Ferengi, Klingon (Gowron), Borg, and Romulan.
Also from Playmates are a set of pencil drawn packaging artwork, including two Borg designs, one of which was used for First Contact packaging, and the Generations Klingon Bird of Prey box art.
Finally from Playmates, one of the (maybe even the) first Star Trek crossovers! A range of four TOS/Teenage Mutant Ninja Turtles figures were released in 1994 and Prop Store have prototype models of each one, accompanied by original design artwork. Most notable among these is Captain Leonardo, who is depicted in a green wrap-style uniform, rather than the regular yellow tunic uniform used for the final production. First Officer Donatello, Chief Medical Officer Raphael, Chief Engineer Michelangelo all seem very close to the final production models.
The final Star Trek item on offer takes us to the real world, and a real rarity; a bronze bust of Gene Roddenberry, one of only three in the world:
This solid bronze bust was commissioned by Dan Madsen, the head of the Official Star Trek Fan Club to memorialize Roddenberry after his death. It was produced in 1992 for Roddenberry's widow, Majel Barrett Roddenberry. Ultimately, only 3 of these were produced: One went to Majel Roddenberry; one went to Star Trek franchise producer Rick Berman; and the final one is presented here. The bust sits on a green marble base with a felt bottom and stands approximately 12 1/2" tall. An engraved metal plaque reads: "Gene Roddenberry, sculpture by: Lawrence Noble."
You'll find full details of all of the above, including many more images of each, and details of how to enter the auction, on the Prop Store listings. And if you have a wider interest in toys, you'll also find there a whole load of other stuff, from Star Wars to Lord of the Rings and a whole bunch besides!