There is not so much  the Boss fanfictions  but i found some of them. What language you can read ?

English (mainly ) , Spanish (as much as English) , Malay, Indonesian( as much as English and Spanish) , Tagalog (Filipino; as much as English, Spanish, Indonesian) , Polish( what i found in Net was fluff romance:Mika x girl oc and second; boyx boy: Karam & Dari from Dalmatian;), Thai, Russian, French. Sadly i did not see more languages, but if somebody knows if there are fanfics about THE Boss /DGNA in other languages, let me know and i will update

credit :text belongs to me

source : The Boss fan sites, google.