A Tardis-esque anomaly within a house (Similar to that room making thing) that has a city within it (Will explain in further detail soon.)
A SCP that isn't there. The files appeared one day, but the object does not exist.
A state of mind and instructions on how to reach that state of mind.
A room containing three people stuck within a 10 minute time loop. They remember everything.
A car that causes sudden and horrible things to happen whenever the ignition is started without the driver wearing his seat belt.