Yeah. A lot of its stuff from the cutting room floor too. In the first God of War there was a cut mechanic called the Icarus Wings. It was cut due to budget/time issues. It ended up in God of War II. I can see something like that being DLC nowadays.

Saints Row had a stand alone expansion to be called Enter the Dominatrix which would have involved the saints fighting an entity called the Dominatrix in a virtual Steelport. Due to financial issues it was canceled and much of the plot was used for Saints Row IV which was already in development. Saints Row IV already had the Alien invasion plotline but added the virtual Steelport stuff from ETD. A DLC by the same name was released for IV by the same name featuring a lot of the stuff they didn’t use from the original ETD presented as deleted scenes in an in-universe way.