From Campaign Games miniatures came Austrian Jägers command and Brunswick too (looking roughly the same/ Korsehut wearing lads). Landwher in 18mm and engineers can be done from the same stock of pics. I needed the officers to have variants for the Landwehr, so the numerous horn blowers lost rifles, horns and extra pay becoming modest rear area guys.
Mixing up the slightly bigger Old Glory and Blue Moon brits in cut coats and slouch hats. Some Peter pigs could be added to Blue Moon units , not to Old Glory ones, the sizes difference too striking (and the muskets would no be tailored hey?).
All three brands of Iroquois/ 5 nations and co. Less trouble with sizes as used in looser groups and the smaller ones will go to groups of "young warriors" together with some veteran older irregulars, minifigs and you name it nimis I had in the 80s(!!) waiting patiently knowing the North American Bug would catch back one day or another.