My Little Pony

My Little Pony was a popular series of toys.

Santa Claus, in an attempt to convince Shona McCullough that he was real, said three words to her: "my little pony". This caused her to react defensively and hold her fingernails to his face, threatening to "mark" him. (TV: Last Christmas)

Information from invalid sources
In January 1992, Dapol teamed up with the manufacturers of My Little Pony to create Rainbow Daleks. (NOTVALID: The Year Ahead)

Influence
This popular toy series spawned a franchise which included comic and television adaptations that have been influenced by Doctor Who.

Television
Some background characters in the television series resemble pony versions of the Master, Third, Fifth, Eleventh, and most notably Tenth Doctors. The, originally a background character nicknamed "Doctor Whooves" by fans (based on his hourglass marking) was later called "Time Turner" in 2012, but this was later changed to "Dr. Hooves" in 2013.

A pony named has also been seen twice in the company of Dr. Hooves. The (It Ain't Easy Being Breezies) in particular also showed Hooves wearing 3D glasses in her company, as in Doomsday, where instead of Cybermen or Daleks they send Breezies back through a dimensional rift.

The allusion is made far more explicit in the 100th episode Slice of Life, where he is called Doctor/Doc, speaks with an English accent, is fascinated by science and time travel, having studied them for "centuries", wears a bow tie and later a long, colourful scarf, and even yells "Allons-y!".

Comics
went beyond the hourglass mark and also parodied the hat, curly hair and scarf of the Fourth Doctor.

references the orange-brown scarf of the Fourth Doctor, a street lamp shaped like the TARDIS and a pony-shaped Weeping Angel.

The Phoenix Comics variant cover for issue 20 features Dr. Hooves eyeing a toy of a Dalek.

In issue 24, a reformed antagonist named Discord wore a fez as he beat up the aforementioned Dr. Hooves and stole his time machine. Later in the same issue, when Discord travelled to the future, he came across ponies who appeared strikingly like Cybermen.

Manga
In My Little Pony: The Manga, Spike came across an alternate universe Dr. Hooves in a muffin-shaped TARDIS with his companion, an alternate Derpy Hooves when he was attempting to save Pinkie Pie from being lost in the multiverse. With his help, they were able to save Pinkie Pie and bring her back. The Doctor Hooves from Pinkie's home dimension offered his assistance in helping the alternate doctor, but the alternate doctor refused, stating that his timeline has had enough damage for one day.

Films
In Equestria Girls: Gift Unwrapped, Twilight likely references Dr. Who after the Flim Flam Brothers scammed the Apple family when she said "That's horrible, and to think Bow Ties used to be a symbol of integrity that only cool people wore", which was likely a reference to the "Bow Ties are cool" line made popular by the Eleventh Doctor.

Actors

 * Tara Strong, who voiced Harley Quinn in the crossover short, Doctor, Doctor, Doctor, voiced Twilight Sparkle, the main protagonist of Friendship is Magic.
 * John de Lancie, who played Allen Shapiro in Torchwood, voiced Discord, also on Friendship is Magic.

Merchandise

 * DWM 481 advertised the Dr. Hooves pony toy as a stocking stuffer.

Comic artists

 * Jack Lawrence drew for IDW's Friendship is Magic and crossover mini-series, Friendship in Disguise.