Memorial University of Newfoundland has many historical collections. Some information is available on line. Detailed information and research services also appear to be available,
This the main page for the Maritime History Archive;
https://mha.mun.ca/mha/index.php
This page describes the holdings and collections available
https://mha.mun.ca/mha/holdings/genealog.php
Data on individuals, families and businesses that were involved in the settlement, fisheries and trade of Newfoundland from earliest settlement to 1850.
Collections of over 5,000 research papers completed by graduate and undergraduate students. The majority of the papers are on community and family histories. Can be scanned, charge per page.
Census of Immigrants 1921-1938
Newfoundland Census Records Collection, Dates: 1794-1801
Newfoundland Plantation Books Collection: 1804-1810
Surnames from Births, Deaths and Marriages in Newfoundland Newspapers, 1810-1890
Irish Parish Records Collection, 1671-1900
Some collections can be purchased,
https://mha.mun.ca/mha/publications.php
I have also added this information as a comment on the Newfoundland Resources page.