1) Fallout New Vegas Dead Money: “Ghosts” wearing gas masks, “I am NOT your mummy” carved into a pillar of the casino/hotel.
2) Fallout 1: Vault Dweller can approach the TARDIS which then dematerializes.
3) Fallout New Vegas Old World Blues: Trauma Override Suits trap and reanimate skeletons which will say “Hey, who turned out the lights?”
4) Fallout New Vegas: Securitrons (robotic police) will yell Exterminate during combat.
5) Fallout New Vegas Old World Blues: Sonic Emitter (left) is similar in design and function to Captain Jack Harkness’ sonic blaster (right).
Fallout New Vegas: NCR Emergency radio will say “Bravo Bravo Charlie, The Doctor is coming.”
BBC The Doctor
Doctor Who references in Bethesda’s Fallout games (all are present in non-modded games and DLCs).