My biography of William Hatchett is here (but NB The Literary Encyclopedia is a subscription site). There appears to be nothing else about Hatchett online!
Facsimile Texts and Downloadable pdfs
Below are links to eighteenth-century editions of works by William Hatchett (the item numbers are from my Bibliography of Eliza Haywood (2004)) that are on Google Books, The Internet Archive, etc. This list is not complete, but I'll add items as I find them.
Dd.1.1a The Adventures of Abdalla (1729)
Dd.1.1b The Adventures of Abdalla, 2nd ed. (1730) NEW
Dd.3.1 The Morals of Princes (1729) [University of Michigan copy]
Dd.3.1 The Morals of Princes (1729) [University of Madrid copy] ¶ This copy was not recorded in my Bibliography.
Dd.10.1 A Remarkable Cause on a Note of Hand (1742) NEW
Works attributed to Hatchett
De.1.2 The Fall of Mortimer, 2nd ed. (1731)
De.5 Remarks on an historical play, called, The Fall of Mortimer (1731) NEW
[Last updated 19 February 2015]