Yahoo
Before Google came into existence Yahoo was the most popular search engine out there. “Yahoo” was the code word to remember to buy stock for in the movie Frequency starring Dennis Quaid. In 2010 Yahoo started using Bing’s search results in its SERPs (search engine results pages).
Yandex
Yandex is the most popular search engine used in Russia that was founded in 1997 and is frequently listed to use in SEO (search engine optimization) software.