Default in Tor and Brave. Search Engine that works and doesn't store your searches. Not fully Open Source. Gets money from un-targeted ads at the top of results.
Open Source and can be self-hosted. May not have as quality of results as some of the other providers.
Also doesn't track you. Pays Google to use their search engine. Also earns its money from un-targeted ads (citation).
Ecosia's mission is to use the revenue generated by their ads and use them to plant trees. They proxy Bing search results. Has a minimal amount of tracking, but it respects Do Not Track requests.