Hessians

Hessians serve with the British and any of the other allies of the Hanseatic League states from which they are birthed. Hessians were conscripted from the populace belonging to the Land Grafs, literally a more modern version of the Lord/Serf relationship. They are NOT mercenaries in the traditional sense, not serving the highest bidder. They belong to the lord and are usually disposed based on the lines of familial/noble obligations. The Hessians of Hesse-Kassel served in North America during the Revolution because of family ties between the Hesse-Kassel Land Graf and King George, so there are tremendously convoluted political forces associated with Hessians. Unlike regular soldiers or regiments like the Hanseatic Army, they are 'household' troops. They were terror troops during the 18th century only as they were among of the only full time soldiers fielded. They and the British Red Coats were two of the only formations that were "professional soldiers". The politics associated with Hessians tells interesting story because they are a noble's troops, not the government's. As such they can create friction within their own government, no less others.

In the 18th century, Hessian's equipment was always issued by the Land Graf, which meant they were usually better equipped as their formations were relatively small. In the modern world, that situation is often reversed in terms of equipment like heavy weapons, airships, and the sort of equipment that requires funding by a government. There are of course, exceptions, but for the most part, Hessians would probably be very specifically armed for certain tasks. For instance, they might be equipped with a small number of airships like Air Lancers. The Panzer Grenadiers who gained fame holding off the Ottomans during the fall of Malta wouldn't work as Hessians. Such formations of tanks require the manufacturing and financial resources of an entire government. A couple of airships is something a very well off Land Graf could afford.