The most well-known uses of tanks during WWI were on the Western Front, but were they used on other fronts (Italy, Gallipoli, Eastern Front, etc.)?
The British used tanks and gas in the Near East from the Second Battle of Gaza (17-19 April 1917). The Ottomans were apparently not overly impressed.
Over three days of battle, the Ottomans held their lines and drove the British into retreat with heavy losses. None of the British "secret weapons" had daunted the Turks, who had not noticed the gas and managed to destroy three of the eight British tanks.
Source: Eugene Rogan, The Fall of the Ottomans: The Great War in the Middle East, 1914-1920