Ki-43, at least two versions
P-40, fill out selection (true B, F and maybe the N).
Yak-3, and maybe a another Yak-9 variant
Beaufighter, two versions
Ki-61, redo and add another variant (maybe even Ki-100)
C.202 and C.205, redo and add C.200
B-26B, redo
Also, in no particular order....
Ki-44
Lagg-3 (for 1941 and early war scenarios)
Fiat G55
Pe-2
P-47, add D-10 and give D-11 paddle blade prop (D-11 would become D-10, and D-11 would get revised performance model and wing pylons)
J2M3
He-111 (would get limited use in LWMA, but useful in EWMA)
A-26A
That's enough to keep HTC busy for several years.....