For Germans I use a mix of Bauhaus from Warzone and Urban War Viridians. I think Scotia Grendel has them.
I also have some Artizan pulp Germans from the Thrilling Tales line including two robots. Only downside is the WW2 guns but I like the rest of the retro sci-fi feel.
For Japanese some of the Void 'Urban War' Triads , but also other Void 1.1 are great Manga style powered armour troops.
Also Warzone had a Japanese faction but they were a bit over the top.