So far I have noticed:
Song from 15 million merits is played on Crocodile and sung by a female soldier on Men Under Fire
Nosedive is the name of a game in Bandersnatch and there's a Metal Head poster in the game company offices
Hotshots, the talent game show on 15 million merits is referenced by the hotel receptionist in Crocodile
The memory capture technology from Entire history of you is used in Men Under Fire
There are loads in Black Museum! I'm rewatching that one next.