Paper Size Chart | Paper Sizes Chart
A series paper sizes with comparison to Letter and Legal size by Bromskloss
Here are some links to his work that gives larger examples of the Illustrations above:
Many paper size standards conventions have existed at different times and in different countries. Today there is one widespread international ISO standard (including A4, B3, C4, etc.) and a localized standard used in North America (including letter, legal, ledger, etc.). The paper sizes affect writing paper, stationery, cards, and some printed documents.* The standards also have related sizes for envelopes and Plotter Paper Rolls.
* information from research on Wikipedia