For those who consider building tanks I suggest to take a closer look on these sets of decals from Bison. Having many really good kits of vehicles you can widen your choice I think, mostly for the vahicles used in Italy by the II Corp.
LINK
and the Echelon decals
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This is a short list of the figures of polish soldiers from the 1939 Army
Adalbertus:
35001 — Polish Infantryman 1939
35002 — Polish Infantry NCO 1939
35003 — Polish Infantryman w/ wz.35 “Ur” AT Rifle 1939
35017 — Polish Infantry Officer, Wizna, September 1939
35018 — Polish Sentry, Westerplatte, September 1939
35019 — Westerplatte (#35017 #35018), September 1939
ARMO:
35901 September '39 – Polish soldiers (2 fig.)
35902 September '39 - Polish soldiers (2 fig.)
35903 September '39 - Polish soldiers (2 fig.)
Dragon:
6344 — "28th Infantry Division" set contains a Polish POW soldier amongst Germans
Mirage-Hobby:
513 35001 - Polish 10th Cavalry (Motorised) Officer 1939
515 35003 - Polish Tank Crew (set of 2fig.) 1939
516 35004 - Polish Infantryman 1939
517 35005 - Polish Motorized Artillery Officer 1939
518 35006 - Polish Mechanic Washing a Tank 1939
S-Model:
E008 Polish soldiers 1939 r. – set I (5 fig.)
E009 Polish soldiers 1939 - set II (5 fig.)
E014 Polish soldiers 1939 r. – set IV
E041 Polish officers of the 10th Cavalry (Motorized)-1939