I think I would clean house!
My top 15...
1: Klingon/Eminian
sidearms
2: McCoy's "
saltshaker" handheld mid-scanner.
3: The
Kolos box!
4: The M-5 computer (or the
Beta V, rigged to pop out of an ordinary wall)
5: Gary Seven's
fake ID's, and his
killer pen
6: The
props from the court-martial room in "The Menagerie" (ship's computer/server, viewscreen, ship's bell, and those flags-- I want to see what they looked like!) PLUS: The
computer/server racks from "The Menagerie, Part 1" and "The Immunity Syndrome"
7: The
pistols used by "Cage" Enterprise crewmen
8:
Scotty's magnetic probe from "That Which Survives"
9:
Kirk's phaser rifle from "Where No Man Has Gone Before"
10: The
TOS Romulan uniform
11: The
"Lawgivers" robes and tubes from "Return of the Archons"
12: The
encased Enterprise micro-miniature from "Catspaw"
13:
Kyle's agonizer device from "Mirror, Mirror"
14: Kirk's
bomb and anti-grav from "Obseesion"
15: Spock's/Flint's
remote control/PDA from "That Which Survives"/"Requiem for Methuselah"
Going back over the list of TOS eps on Memory Alpha, what strikes me is how simple and rare these special props are. TOS writers and producers often relied on clever tricks, voice-overs and other non-FX to create the illusion of something unusual or super-high-tech. Many of these non-FX, like the self-destruct sequence or the anti-gravs, give the illusion of something powerful that relied more on imagination than expensive theatrics.
But I think if there's something unique I want to try on the TOS set when nobody's looking, it would be to try out
Kirk's quarters and see what they're like.