This poster represents Nikolai II's abdication. It's called A Memento of the People's Victory, Nikolai Romanov Surrenders His Crown to His Vanquishers

This is a poster depicting Lenin's return to Russia in April 1917--note that it was done in 1927, some years after his death, when he was being actively heroicized. Lenin was much scrawnier than this in real life!
Text: And long live the Socialist Revolution Throughout the Whole World!

These two are (apparently) Socialist Revolutionary party Constituent Assembly campaign posters--note that ID info at side completely wrong, if you happen to read Russian.

Text: Land and Freedom Will be Given to You By the Soviet of Peasants' Deputies and the Party of the Socialist Revolutionaries

Text: Soc. Rev. party. You will win your rights through struggle (on the banner). Land and freedom (on the globe).