I'm convinced there is a decent amount left over from the original cancelled 2007 version of the video game Splinter Cell: Conviction. Long story short the game was originally supposed to have Sam Fischer dressed like a bum and using makeshift weapons in urban city environments complete with crowd-blending mechanics(that were unintentionally similar to Assassins Creed which reportedly played a role in the game being significantly retooled for the final release, as the E3 presentation was not well received for the most part with more then a few thinking the game was ripping off AC)while he flashes back to memories of his daughter Sara(presumably she wasn't going to have been revealed to still be alive like she was in the final game).
I'm also sure that the cancelled video game This Is Vegas is still complete somewhere in WB's archives(After they bought out Midway's assets there was brief talk of them mentioning considering publishing the game since it was basically done but they ultimately cancelled it).
In Scary Movie, during the first chase scene with Cindy and The Killer, a Jamie Lee Curtis cameo was planned where she would hide inside a closet and force Cindy out, and they would get into a fight over who got to claim the hiding spot, which later got cut.
Not sure if it’s 100% likely, but given there’s a jump cut in the final film that looks like Cindy was right about to go inside the closet tells me that they filmed that scene. If they did, it has never seen the light of day.