The World of Warcraft is going back to its roots with WoW Classic. Giving players the chance to return to the game as it was around the time of its launch, WoW Classic is set to launch worldwide on August 27. However, ahead of its imminent release, the team at Blizzard are offering a closed beta test for WoW Classic, and we've got all the details players need to jump in on the action.
At some point, Zygor was destroyed. Accounts differed as to what the cause of this was and when it happened. According to one account, the planet was destroyed in the war against the Xaranti. (PROSE: The Bodysnatchers) Another account given by the Zygon Broton in the 20th century said his world was destroyed in a "recent catastrophe". (TV: Terror of the Zygons) Another account, given by Elizabeth I who had been posing as a Zygon in 1562, said that the Zygons lost their world when it burned in the first days of the Time War. (TV: The Day of the Doctor)
Only really to expand on Gráinne's comment as regards the 'collecting' and 'roster development' sections - which are, as said 'distinct' although they are intrinsically linked - I would like to point you in the direction of the in-game Achievements > Battle Pets > Collect tab. There are a series of achievements called Raiding With Leashes, pretty much all of which can be completed via the auction house - if you have the gold/inclination - or by completing old raids.