A weapon reverse-engineered from a ship called the "Jathaa sunglider" is first seen in The Christmas Invasion, where it is a powerful beam weapon used to wipe out a Sycorax ship. Its later discovered in the episode Army of Ghosts, that Torchwood One shot down the sunglider.
A scaled down version of the same weapon is seen in The Poison Sky aboard UNIT's aircraft carrier the Valiant. It was used to attack a Sontaran stronghold.
Koh-i-Noor Diamond
This famous diamond was designed to be part of a telescopic device designed to focus a beam of moonlight to trap and eventually destroy the physical form of a werewolf in Tooth and Claw.
Deadlock seal
Introduced in School Reunion, a deadlock seal is a type of locking mechanism that stops all sonic devices from opening. Since then, deadlock seals are often used as a plot device to prevent the Doctor from using his sonic screwdriver as an easy escape. The TARDIS itself can also be deadlocked, preventing even those with keys from entering; it does not, however, prevent the sonic screwdriver from interfering with the ship itself.
Ice Gun
A fire extinguisher used to immobilise the Clockwork Droids in The Girl in the Fireplace. The name "ice gun" was suggested by Mickey, and the Doctor called it a fire extinguisher.
A Power Cell
A small and insignificent part of the TARDIS which continues to glow when the rest of the ship 'dies' after crashing into a parallel world. The Doctor gives up ten years of his life in order to charge up the cell so it can reboot the TARDIS.
Glasses
Basically, a pair of 3-D glasses. The different colour lenses are used by The Doctor to examine the void ship, the Daleks, and the "ghosts" in the episodes Army of Ghosts/Doomsday. They can detect the radiation or 'void stuff' given off by anything that has crossed between dimensions.
Magna clamp
These clamps negate the weight of the things they are attached to, allowing a single person to easily lift something weighing several tonnes. In Doomsday the Doctor and Rose use these clamps to attach themselves to the walls of Torchwood to prevent themselves from being sucked into the Void.
Genesis Ark
Originally created by the Time Lords, the Genesis Ark is a Dalek-shaped prison ship that contains millions of captured Daleks. Like the TARDIS, it is bigger on the inside, yet is only large enough to release one Dalek at a time.
