Fan theories (volume five)

Pokémon, Stargate, Sanctuary and The Culture:

What if the result of Subliming turns one into a Pokémon? In other words, Culture "heaven" is a Nintendo role-playing game.  

Similarly, the Elder Races include the Dra'azon from "Consider Phlebas" and the Ancients from the Stargate franchise.

What if R2-D2 was a Special Circumstances agent, thus connecting the Culture novels with the Star Wars universe and dating the films? Consider how the films could have ended if one extra plucky droid wasn't there to help or enable the main players.

Similarly again, the characters Helen Magus and Bigfoot could actually be aliens if the programme is set in the same galaxy as the Culture despite claims otherwise. Magus and Bigfoot are simply exiles from the Culture, or other human aliens, living on Earth with claims of "abnormality" as their alibi.

Fan Theories volume four

Fan theory four:

Science fiction television programmes featuring humanoid aliens are all set in the same universe as the Culture. The difference is that these programmes portray aliens as humans would imagine them to look like. The events portrayed are after the Culture makes contact with Earth but Humans can't take there being other humans "out there" that look just like them so, in their minds collectively, aliens look a lot different.

This theory also allows for the Drakh and Vorlons to be offshoots of the Culture, or that Babylon 5 is actually anti-Culture propaganda. This reflects the policies of the two races and the mobile nature of their civilisations.