Long ago, Spiros Koumousis, the late, but very enthusiastic owner of Alphacast, did a series of articles for Miniature Wargames showing Ottomans for the Greek War of Independence (1820s) in baggy trousers, sleeveless jackets, and turbans. I used 25 mm Minifig Great Northern War Turks for these. There had been Turks in uniforms for the Napoleonic period, but my understanding is that this offended the janissaries, and such uniforms had gone away by the beginning of the Greek War of Independence.
I believe Foundry makes Turkish infantry for the Crimean War in uniforms. They also have bashi-bazouk cavalry and a set of horsemen in "Arab" dress. (1850s)
Askari Miniatures makes Turks for the Russo-Turkish War of 1877-78. By this time, the Ottomans had a blue uniform cut very much like that of the French or American Civil War Zouaves. They also have some Moroccans who might work for late period bashi-bazouks, if you are pitting Montenegrin, Serb, Bulgarian, Greek, or Albanian irregulars against Turkish irregulars in the early 1900s.
By the late 1880s and up to 1900 or so, the Turkish army was wearing fez, tunic, and trousers, just like the Egyptian army (technically Egypt was still a part of the Ottoman Empire at that time). I used Old Glory Egyptians for my 1897 Turkish army, but Essex and other companies with colonial lines are also good.
Finally, Woodbine Design (Gripping Beast) sells World War I figures in puttees and sun helmets.
Aside from these, a number of companies make individual packages that would supplement some of these periods. Pulp Figures' Istanbul Constabulary set is one of these.
So, there are some ideas.
Grelber