Tersurus

Tersurus was a planet with singing stones and clone banks. (PROSE: All-Consuming Fire) It was mentioned as being in the "Outer Planets" in the Matrix. (AUDIO: Neverland)

History
In the Old Time, the Other sent Susan Foreman to Tersurus during the Great Schism so that she would be safe from the civil war erupting on Gallifrey. (PROSE: Lungbarrow)

The Memeovore came to Tersurus during the War in Heaven and consumed the Tersurans' forms of communication, so they had to evolve other, more tenuous forms (PROSE: The Taking of Planet 5) using farting. (TV: The Curse of Fatal Death)

When travelled with Susan Foreman in his TARDIS to Tersurus, it was a lifeless planet with barely anything but rocks and lichen. Susan attacked the Master and left him to die there. (PROSE: Legacy of the Daleks) According to another account, however, attempted to attack a Time Lord outpost on the planet, and was left disfigured after a confrontation with a, as part of a plan to join the Cult of the Heretic. (AUDIO: The Two Masters) In any event, a signal sent to Gallifrey by the Master's TARDIS drew Chancellor Goth to Tersurus, where he found the disfigured body of the Master. (TV: The Deadly Assassin)

The Time Lords had an outpost on Tersurus. The Master infiltrated this base on another occasion in order to gain forbidden knowledge on the Dimensioneers. (AUDIO: Dominion)

After his TARDIS was damaged by a vortex parasite, the Eighth Doctor patched it up on Tersurus. (COMIC: A Life of Matter and Death)

After the death of the Tersuran race, one version of the Ninth Doctor met with at Castle Tersurus to tell him the news that he has plans to marry his companion Emma and retire.

The Master then make one final attempt to destroy the Doctor and his companion Emma by plunging them into the vast, labyrinthian sewers of Terserus. He did so by previously travelling back in time and bribing the palace's architect to hide a trap door. However, the Doctor had predicted this, and had gone back in time to also bribe the architect to instead place the Sofa of Reasonable Comfort. Through a series of further subversions, the Master found himself plunged into the sewers.

The sewers being vast and complex, as well as disgusting and treacherous, it took the Master himself 312 years to escape from them, being repeatedly knocked into the sewers on three separate occasions, requiring the Daleks to regress him back to a more youthful state. (TV: The Curse of Fatal Death)

would later recall having spent a long time climbing through the sewers on Tersurus. (AUDIO: The Bekdel Test)

Around the 21st century, Raston Hardware Company manufactured Raston Warrior Robots and Raston lap-dancers in a warehouse on Tersurus' moon, Tersurus Luna. (PROSE: Alien Bodies)

In the 27th century, May Zalrick bought Attow Eels on Tersurus. (AUDIO: The Havoc of Empires)

In 6211, a Sontaran stealth raid destroyed Tersurus with an earthshock bomb which they had obtained from the Cybermen. (PROSE: The Crystal Bucephalus)