I've been using these for quite a while and thought I might share them here. As far as verisimilitude goes, these resources are really helpful for adding an authentic touch to any timeline or story set in the early 20th century. Maybe it's a little too American-centric, but I figured it might be of use to many here regardless.
Western Union telegram template: http://cthulhulives.org/toybox/PROPDOCS/WesternUnion1930.pdf
Generic self mailing telegram template: http://cthulhulives.org/toybox/PROPDOCS/Telegram.pdf
Free font pack that includes a lot of typefaces derived from those that would've been found in newspapers in the '20s and '30s: http://cthulhulives.org/toybox/PROPDOCS/HPLHSFreeFontsOTF.zip
1920s newspaper ingredients (includes period appropriate advertisements, stock photos, and articles): http://cthulhulives.org/toybox/PROPDOCS/NewsPix/1920sNews.zip
Western Union telegram template: http://cthulhulives.org/toybox/PROPDOCS/WesternUnion1930.pdf
Generic self mailing telegram template: http://cthulhulives.org/toybox/PROPDOCS/Telegram.pdf
Free font pack that includes a lot of typefaces derived from those that would've been found in newspapers in the '20s and '30s: http://cthulhulives.org/toybox/PROPDOCS/HPLHSFreeFontsOTF.zip
1920s newspaper ingredients (includes period appropriate advertisements, stock photos, and articles): http://cthulhulives.org/toybox/PROPDOCS/NewsPix/1920sNews.zip