As it was prized by humans; it was an item that could be invested in. During a huge market collapse during Miracle Day, the best advice the people were given was to invest in gold. (TV: End of the Road)
Nero gave Barbara Wright a gold bracelet. (TV: The Romans) The Animus was able to control her through the bracelet. In addition, Ian Chesterton owned a gold pen which disappeared when he went onto the surface of Vortis and took it out. (TV: The Web Planet)
In payment for his service, the Master offered Chang Lee two bags of gold dust that was kept within the Doctor's TARDIS. The Master claimed the dust, along with the TARDIS, had been once his before the Doctor stole it. After the Eighth Doctor defeated the Master, he let Lee take the gold dust. (TV: Doctor Who)
Owing to its non-corrosive nature, gold essentially choked the Cybermen's respiratory systems. The glittergun, a weapon used during the Cyber-Wars, fired gold dust at its targets to exploit this weakness. Adric's badge was gold-edged, allowing for the Doctor to grind it into the Cyber-Leader's chest and asphyxiate him. (TV: Earthshock)
During a time period in which the Cybermen had been reduced to small remnant groups wandering around the galaxy, one group tried to take revenge by making a desperate attempt to blow up the remnants of the planet Voga, a planetoid of pure gold that had wandered into the solar system and had become a moon of Jupiter. They hoped that this would disrupt their enemy's supply of the element. (TV: Revenge of the Cybermen)
While trapped on San Helios, the Tenth Doctor determined that he needed gold to combine the anti-gravity clamps with the systems of the 200 bus. In order to do so, the Doctor took the golden Cup of Athelstan from Lady Christina de Souza, smashed it to bits with a hammer and successfully used the gold to combine the two systems. As a result, the Doctor was able to fly the bus back through the wormhole to Earth. (TV: Planet of the Dead)
After the Sky vessel crashed in Nottingham in the 12th century, the robotic knights manning the ship worked with the Sheriff of Nottingham to use gold to repair the ship's engines. To this end, the Sheriff stole the gold from the local population for their use. While onboard the ship, the Twelfth Doctor didn't believe that the knights had enough gold to repair the ship.
After the Sheriff was killed when Robin Hood knocked him into a vat of molten gold, the two remaining knights launched their ship. The Doctor recognised that the ship lacked enough gold content to make it and if it exploded on Earth, it would take out "half the country." Working together, the Doctor, Robin Hood and Clara Oswald shot a golden arrow into one of the engines, providing enough gold content for the ship to make it into orbit. Once there, the engines went critical and the ship harmlessly exploded. (TV: Robot of Sherwood)