LEGO

LEGO, sometimes spelt Lego, was a children's (and often adult's) building block system that produced "ordinary space LEGO", as well as Star Wars-themed sets. (AUDIO: Memory Lane)

The Thirteenth Doctor claimed she was a Doctor of LEGO. (TV: The Tsuranga Conundrum)

They didn't have spaceship LEGO when Tom Braudy's grandmother grew up. Tom thought that space LEGO was for boys only, while girls liked building hairdressers and flower shops. He built a ship to go to Mars, and then a bigger one to go to Jupiter the next week, before the Eighth Doctor and companions materialised the TARDIS in their sitting room. (AUDIO: Memory Lane)

Space-themed sets were produced in Ace's time as well, who crashed spaceships into LEGO police stations in her early youth. (PROSE: Set Piece)

LEGO minifigures were tiny in comparison to real people. (PROSE: History 101)

In fact, nearly all LEGO models were significantly smaller than their real world equivalents. According to the Eighth Doctor, Toronto in the summer looked like "a giant LEGO set" from above the CN Tower. (PROSE: Trading Futures)

Joseph similarly compared the skycrapers of New York City to LEGO buildings when atop the Empire State Building. (PROSE: Salvation)

The Savant, a great alien hacker of both computers and the human brain, enjoyed both eating LEGO as a snack, and bathing in it. Sarah Swan dubbed him "a hormone-secreting, Lego-obsessed Sesame Street monster". (PROSE: Blue Box)

Bernice Summerfield at some point did an archaeological dig in an Earth Legoland. (PROSE: Nobody's Children) She frequently had dreams of a bearded villain turning her into LEGO. (PROSE: Beige Planet Mars)

The children's toy Parablox was made of several multicoloured interlocking bricks made of plastic polymer and threaded with a minimum-lode biodata stream. Sets included the Universe in a Cardboard Box. (PROSE: The Book of the War)

The Eleventh Doctor kept a LEGO room in his TARDIS. (COMIC: Sky Jacks)

According to Toshiko Sato, the two halves of a quantum transducer fit together like LEGO. (TV: Ghost Machine)

Incopolis' streets were filled with buildings too similar in design that they looked like "they'd all been assembled from the same Lego kit". (PROSE: Seeing I)

Liz Shaw compared the Seventh Doctor sifting through laboratory equipment to a child receiving a new set of LEGO. (PROSE: Blood Heat)

Gideon Crane mockingly referred to Gallifrey as Legoland. (AUDIO: Minuet in Hell)

The Celestial Toymaker created a castle in the sky above Stockbridge which appeared to be made of LEGO. (COMIC: Endgame)

On Osgood's desktop, there was a icon with a picture of a LEGO-like Thirteenth Doctor. (WC: The Zygon Isolation)

Behind the scenes
In 2015, LEGO began releasing products related to Doctor Who. On 29 September, LEGO Dimensions was released, with the Doctor and a Cyberman as playable characters. The plot of Lego Dimensions showed the Doctor Who universe as existing within the "LEGO multiverse". Later that year, a LEGO set was released, with six minifigures and a TARDIS minifigure, which could be converted into a scenario.

In 2017, The LEGO Batman Movie continued the trend of Doctor Who being in the Lego multiverse by showing Daleks as one of many villains imprisoned in the interdimensional Phantom Zone. 2019's The Lego Movie 2: The Second Part briefly features the Doctor's TARDIS as one of many pop culture time machines which are taken apart and rebuilt into a single time machine.

The LEGO Thirteenth Doctor pictured in The Zygon Isolation is real, as it's a custom produced by a website called minifigs.me.