General

Archive.is - a webpage archival site

Digital Public Library of America - Discover 47 million images, texts, videos, and sounds from across the US

Old Bailey Online - trials and biographcal details of ~2,500 men and women execued at Tyburn, London

The Internet Archive

International Coalition on Newspapers (ICON)

Elephind - Newspaper search tool that enables searching across various digital newspaper collections (more than 1,000 titles presently included).

Europeana Newspapers - More than 18 million newspaper pages from 18 partner institutions.

Newspapers.com - Digitized newspapers from U.S., Canada, and England reportedly covering the 1700s to the 2000s. From Ancestry.com

NewspaperARCHIVE - Archive of U.S. and international newspapers.

Google News Archive - Freely accessible historical newspapers from the U.S., Canada, Mexico, and select other countries.

Chronicling America: Historic Newspapers - Old American Newspaper archive

Trove Australian Newspaper Archive - Australian Newspaper Archive