Image Search and Identification
Wenku — download documents from Baidu Wenku without registration
Afrobarometer — huge database of the results of sociological surveys conducted in African countries over the last 20 years
Arabbarometer — database of the results of sociological surveys conducted in the Arab countries of Africa and the Middle East in 2007-2018
Archives
Web Archives — extension for viewing cached web page version in 18 search engines and services
EasyCache — quick search website old versions in different search engines and archives
Search engines
Web Search Navigator — extension that adds keyboard shortcuts to Google, YouTube, Github, Amazon, and others
Tumblr
Tumblr Tool — collected posts tagged with a specific term from Tumblr and export to .tab file (opens in Excel) and .GDF (opens in Gephi)