Bolsheviks like Trotsky, Lenin, Kamenev, Sverdlov etc conspired in 1916-1917 to take over the Russian Empire.
The Sicilian mafia in the 1920s conspired to take over organized crime in America
JFK assassination: There was a second gunman that fired the fatal shot. Oswald was part of a conspiracy and didn't act alone.
The moon landing: it did really happen.
There are no extra-terrestrials on earth flying UFOs (but there may be many terrestrial UFOs, possibly military experiments).
There are no reptilians.
Illuminati: They don't really exist as such. There really are billionaire globalists like George Soros who seek to undermine civilization.