I would suggest:-
1. Portuguese:- Infantry (march attack poses, but please without the musket slung on the shoulder in such large numbers). Cavalry, artillery. For the Peninsular campaign with the British.
2. Technical personnel like sappers, engineers.
4. Mounted command with appropriate attendants/aids etc. Very useful for wargaming.
5. Ottomans would be very colourful and interesting and could be used for a wide range of things I suspect so could be very flexible. I think they fought both the French and Russians.
6. British Peninsular campaign with stove-pipe shako with a variety of infantry "march-attack" poses (and again, please without large numbers of slung muskets). Artillery and Cavalry.
I really love the recently produced figures, the variety and quality of the March attack poses are very useful.