It is awfully lucky to find phone, business and farmers directories from the former Russian Empire and USSR online. GenealogyIndexer.org has an incredible list of links for these directories.
The webpage has links to directories from Russia, Ukraine, Lithuania, Latvia, Estonia and Belarus, in addition to former Eastern Block countries and other western and eastern European countries.
Since borders have changed over the years, please make sure to check the whole list. Directories for Lviv, now in western Ukraine, is listed under Poland. Bialystok, once part of the Russian Empire, is now in Poland and among the Poland links.
These directories will not be as easy to leaf through as 21st century directories but it is well worth checking out these directories. With so many records destroyed during the eastern Europe’s communist era, any information from the early 20th century is a blessing.
So go check out these directories at GenealogyIndexer.org to see whether your relatives or ancestors are mentioned in these directories. Gems of information may be waiting to be discovered.