From TARDIS Index File, the free Doctor Who reference.

Reindeer
Appearances:	2009 BBC Christmas idents

This article is written from the Real World point of view.

A reindeer as a "special guest" in several short, non-canonical promotional videos produced for BBC One in 2009 for broadcast at Christmas of that year. The spots feature David Tennant, in character as the Tenth Doctor, cavorting in a snow-covered forest with the TARDIS and a reindeer. In the longest video of the promotion, the Doctor hooks several reindeer up to the TARDIS, and they take flight (suggesting they are flying reindeer like that used by Santa Claus). Two short "sting" promos of about 10 seconds each show a singular reindeer wandering around the outside of the TARDIS.

The promotional videos are not part of continuity, though they will be included in a DVD/Blu-Ray box set release of the 2009 Specials scheduled for early 2010.

From Muppet Wiki

The Reindeer are five of Santa's famous sleigh-pullers, featured in a repeated TV Christmas skit. The group consisted of boss Dasher (aka Charlie), Dancer, Donder, Prancer, and Blitzen. The reindeer made various bad puns, broke into random carols, and attempted to make it snow with a "snow dance".

First appearing on the Christmas installment of Perry Como's Kraft Music Hall on December 20, 1965, the reindeer re-appeared on The Ed Sullivan Show on Dec. 22, 1968. The reindeer were built by Don Sahlin, and their voices were performed by Jim Henson (Dasher, Donner), Frank Oz (Prancer), Jerry Juhl (Blitzen), and Bob Payne (Dancer).

The Ed Sullivan Show version was included on the Muppets Magic from the Ed Sullivan Show DVD.

Other reindeer include:

Lightning

Charles Blitzen

Characters as Reindeer

• A team of monsters played reindeer in A Muppet Family Christmas.
• Wontkins appeared as a reindeer in a Wilkins Coffee commercial.
• Rizzo and the rats appeared as "ratdeers" in It's A Very Merry Muppet Christmas Movie.

From GuildWiki

Reindeer
Classification
Species: Animal Profession: Level(s): 1

Uncharmable and un-attackable creatures which roam the Far Shiverpeaks. They will show up as NPCs on your compass.

Location

• Far Shiverpeaks
  • Drakkar Lake
  • Jaga Moraine

They are a random spawn and will not always be present in either area.