Roblox

Roblox is a and   developed by the Roblox Corporation and launched publicly on 1 September 2006.

Crossovers
Roblox has had one official crossover with Doctor Who.

On 11 March 2020, the Roblox Corporation announced a partnership with BBC Studios, that would culminate in the release of a limited range of Doctor Who-themed virtual items from 12 March to 26 March. There was no narrative material released as a part of this collaboration, although there have been a number of unlicensed fan games, which often showcase operable TARDISes.

In the announcement on doctorwho.tv, the Global Franchise Head of Marketing for Drama, Sarah Bold, was quoted, where she spoke about the "joy" it was for BBC Studios to take Doctor Who to Roblox, where "millions of fans [would] be able to play and create with these new items."

References to the DWU in Roblox media
Roblox, occasionally, released accessories that included cultural references to Doctor Who: the head accessory Cyrofreezer, released on 3 February 2010, is clearly based upon the CyberNomads; the head accessory Voidbot, released on 6 September 2011, seems to have been inspired by the general design of the Cybermen; and the head accessory Deluxe Fez, released on 2 November 2012, has a reference to the Eleventh Doctor, as the item description reads: "It's a fez. I wear a fez now. Fezzes are cool."