Here are some more.

Soviet AT Rifles – PTRD-41, PTRS-41

Germany – Panzerwurfmine, PzB39 Antitank mine Gewehr 98 and all it’s variants Karbiner 98, Gewehr 41(W) and Gewehr 43,

Japan – Type 97 Anti-tank Rifle. Type 100 submachine gun,

UK – Northover Projector (surprise them with this one, it’s a dilly), De Lisle carbine, Various marks of the Vickers Machine Gun, the Vickers-Berthier light machine gun,

Switzerland – Steyr-Solothurn S1-100

Are you also including the following?

Hand grenades

Rifle Grenades from all combatants.

Flame Throwers?

Squad mortars such as the Japanese 50mm Light mortar?

Italian Brixia?

I guess it may all depend on your definition of "small" arms.

__________________
Best Regards,
JW