The Transylvanian territories of the Kingdom of Hungary during the Napoleonic period yielded various kinds of regiments. Grenzers were recruited from ethnic Serbs in Backa and Banat as well as Romanians and ethnic Germans in those areas and along the Danube border with Ottoman Wallachia. In addition, there were several Hungarian line regiments and one hussar regiment made up largely of ethnic Romanians from Transylvania. A famous one was the 51st regiment, nicknamed the "Legion Infernale" by the French, which (along with the French emigre Bussy Chevaux-Legers regiment) routed the Consular Guard at Marengo. Large numbers of ethnic Romanians also served in the Hungarian "Insurrectio" army that was raised in 1809 and saw action against the French at the Battle of Raab.
As for troops from the Ottoman territories, the ethnic Romanian components consisted primarily of guard detachments of the various local boyar princes to be augmented by a mass peasant levy in wartime. These men wore traditional costume not too dissimilar from the Lucky Toys "Vlad Tzepes" set, though some had firearms at this point. They had almost no military value and, indeed, the Ottomans barely bothered to mobilize them during the Russian invasions of the Danubian principalities in 1806 and 1810, choosing to fight the Russians with units formed primarily from Anatolians, Albanians and Bosnians. The Russians raised auxiliary units of Romanians during their occupations, which were clothed in the style of contemporary Russian infantry.
One other note is that the ethnic Romanians of what is now Moldova were part of the Russian Empire during the Napoleonic Era and were conscripted into regiments in the Russian army, some of whom fought in the Danubian Principalities against the Ottomans. Finally, some ethnic Romanians in the Bukovina region (which is now part of Ukraine) were in the "German" territories of the Hapsburg Monarchy and, as such, served in "German" infantry regiments raised in that area during the Napoleonic Wars. Some may even have served in the Austrian uhlan regiments raised in the area, though those were mostly the province of ethnic Poles and Polonized Ukrainian gentry.