The user interface pictures seem found on the Internet and Edit into in-game format…
Chinese
dragon svg from wiki page，they add a dragonball in it
Japanese
svg of kamon of Tokugawa,Toyotomi and Oda clan
Korean
tiger painting in charm
Vietnamese
modren painting about le loi return the sword to kim quy
Persian
Faravahar svg
Saracens
Bismillah svg
Turks
Seljuk Eagle svg
Berbers
Dynasty shield in Alhambra Palace，edit this picture
Tatars
Girih in Shah-i-zinda, redraw of this picture
Cumans
Kurgan Stelae，this picture
Indians
svg of mughal flag，seems redraw，add some detail
Burmese
redraw of this picture about bagan plain pagoda
Malay
redraw of this picture about majapahit warship
Khmer
garuda svg of Emblem of Thailand
Teutons
redraw of this picture about globus cruciger
Vikings
vegvísir svg
Britons
redraw of tudor rose with cross arrows，tudor rose is inverted
Celts
triquetra svg
Franks
Carolingian cross svg
Burgundians
redraw of Coat of Arms of the Duke of Burgundy since 1430.svg
Bulgarians
redraw of this Pliska Rosette
Magyars
redraw of photo about Holy Crown of Hungary
Lithuanians
Vytis svg
Bohemians
prague clocktower svg but time is different
Italians
biscione style in Milan Stazione Centrale without crown
Portuguese
redraw of this picture about Caravel Model in the Musée national de la Marine
Byzantines
mix this 2 two-headed eagle design
main is right one,delete the sign of center,fix with left one
Spanish
this picture,the Morion helmet
Sicilians
redraw of this picture，peacock in norman palace Palermo
Ethiopians
coin of king ezanas
Malians
mansa musa in Catalan Atlas
Aztecs
the center part of sun stone svg
Mayans
Vision Serpent svg
Incas
A sketch of the relief of Viracocha on the Gate of the Sun
Cannot find the source of the image of the rest but know the image meaning
Slav：helmet of boyars,looks like Nikolskoye helmet
Mongols：sulde
Poles：helmet of hussar with cross of obuch
Goths：helmet of goth warrior
Huns：Turul or common raven？
