Archer Mercs such as Welsh Longbowman.
Scottish Targe-and-swordman which is basically acts like a huskarl, resistant to ranged attacks from Infantry, cavalry, and buildings. Weak against artillery and light artillery such as grenadiers, and Abus gun.
Nepalese Gurkhas, which act as Super-jannissaries, they use the Kukri sword in melee, and a musket for range.
Moughul Mahout, a Mounted skirmisher which rides atop an Elephant, switch to melee to cause trample damage with a splash radius such as a Cuirassier. Good against Infantry, resistant to artillery, and ranged attacks. (Sends infantry flying when they get killed by it)
Korean Rocket Wagon, like an Uberfied Organ gun, shoots multiple rockets at a time causing a great deal of siege damage over a wide area.
Chinese Tigermen a spearman dressed in a tiger suit to scare cavalry, good vs cavalry, fast and lightly armored, like a rodelero.
Chinese Chu-ko-nu that's right their back from AOK, and they fire multiple Rocket-arrows to devastate infantry and buildings alike, think of them as Super-Abusguns.