IEC 60617 symbols with Status = "Released" and Application class = "Circuit diagrams" at least - as it's worldwide accepted standard, backed by respective (multi)national standards like CA CSI, Multinational IEEE, RU ГОСТ/GOST, UK BSI, US ANSI etc. (sorry for not mentioning others, guess they exist...

Thanks for the library! maybe this info will be useful: (1) modern Russian GOST: ГОСТ Р МЭК 60617-DB-12М-2015 Графические символы для схем (в формате базы данных) is the same as modern: IEC 60617-DB-12M:2012 Graphical symbols for diagrams (IDT) - this is directly referenced in official GOST publicat...