For the British/Commonwealth, there are ~
6 Rifles
~ 4 SMG’s
6’ish MG’s
At least 6 Hand Gun’s
2-3 Mortars
At least one excellent LMG
2-3 MG options
Various grenades
At least one Flamethrower
The Boy’s ATR
So at least 15 different options there
Add in planes and tanks
And your getting close to 30 before you even start to look at lend lease potential all for 42.
So by lend lease I mean American kit that was used in theater, not by American troops, depending on the time frame, and how willing they were to stretch it, and they seam pretty willing to stretch reality, this would add even more options, and if they could do the Chinese the list get’s much larger.
The Japanese List of options is also extremely large, almost everything the Japanese had, was available pre war with very few exceptions.
Easy half Dozen Pistol options
At least 3 SMG options
At least a half dozen Rifle options
Knee Mortar, and two or three other mortar options
3 or 4 LMG options
2-3 HMG options
A ton of IJA Army Aircraft options
3-4 tank options
A couple Scout car option’s
Various small Infantry Gun options
ATR rifle option
…
And I am underselling the options, all of which are 42 or earlier with regard to availability.