WW1 Russian partisans on foot and horse is my suggestion.

I like the partisans suggestion as they could work just as well for the RCW and some might even work for WWII partisans. Recently I've been reading GER Gedye's book Fallen Bastions which recounts the turbulent inter war histories of Austria and Czechoslovakia and it occurs to me that a set of fairly generic interwar armed civilians could be really useful. Gedye's book made me want to recreate some of the conflicts between Austrian socialists and fascists and the sort of set I'm suggesting could also be used for all sorts of scenarios such as the Spartacist Revolt, possibly IRA or even the Spanish Civil War. A use for them that I think might be really popular would the VBCW.

Those would be top of my list, too, followed by
- Austro-Hungarian cavalry 1914/15
- Serbian infantry 1914/15
- Serbian artillery crews 1914/15

I am eagerly waiting for HäT to release their 1914 French artillery crews and 1914 Belgians.

This discussion in May 1917 lists further interesting suggestions.
http://pub33.bravenet.com/forum/static/show.php?usernum=2833323740&frmid=6&msgid=1058866&cmd=show

Btw the upcoming Serbian set has lots of men wearing traditional footgear so Balkan Wars armies and WW1 Bulgarians might become easier to scratch?

And yes to WW2 Dutch, and more artillery crews!