First, a Tear gas launcher.
(I remember one they used by a switch to launch a massive bombardment of tear gas over a target. [Its in a BF1 map, and a real use])

Second, a Vickers machine gun.
(This is the wheel'd version, it will lay on the ground.)

Third, A mortar (WW1 era, it does less damage, with HE, AP, and gas.

Thats all i can think of so far, mabey some Biplane strikes.