@ Lucem Mundum
I woukd suggest late Sibir and Kalmyk lancers and also Mordvins for Volga Bulgars
Oh yeah Ryazan-Murom early allied troops as well
Edit actually early mordvins too as tgey were tributary.
Note that the murom were also ugrians of the fino ugric group. Similar to hungarians
Edit. Also baskhirs for both Kazan and the Nogais (high and late cuman kypchak faction alongside the Manghit. Kypchak. Kimeks )
Edit khanty-mansi too
Edit i don t think adding them generic as ural people would help as tgey were pretty diverse
For example khanty many bowmen hunters
Kalmyk heavy lancers
Sibirs same probably HA too
Mordvins heavy cav auxiliary cav probably melee cav