Looks like the spread of Sanskrit is not as limited as what we expect. Some examples are Phags Pa which was created to create a common script to represent the big three – Chinese, Mongol and Sanskrit, Hangul, which potentially descended from Phags Pa, Bonji of Japanese which is nothing but medival Siddham script and this one, Soyombo. All this is because the Tibet uses a Sanskrit derived script and so does Nepal and the traditional Buddhist sites of Bihar.
Soyombo(Svayambhu – self created) Script is an artificial script created based on Ranjana script to write Mongol in 1686 by the scholar Zanabazar.
i, ü, u,e,ö,o,ai,au,ṛ,ḷ(the last two only for Sanskrit). The last character is added to the first set to have longer sounds ā,ī,ǖ,ū and so on.
The complete script is below.
Final consonant diacritics