What were the new technologies of WW1?

Many new technologies were introduced in World War I. A few of the most significant were poisonous gases of various kinds utilized by both sides in the conflict; militarily effective aircraft, both fixed-wing and dirigible types; helmet-design; and armored fighting vehicles or, as the British dubbed them for secrecy purposes, "tanks".
Mechanized warfare, Tanks, also Airplanes.

Flamethrowers, trench mortars, poison gas, barbed wire, and submarines were first used effectively (though not necessarily invented during the conflict).