Proxigram

My negative picks are:

• By default it enables sending usage metrics and local search results which they claim to be anonymous.
• Also unlike other search engines it doesn't have parameters for search query which can be used set your preferences, thus avoiding hustle to configure settings everytime.(in cases like delete cookies when browser closed and incognito mode).

Yeah I've experienced it too and switched to startpage.

So far what I know are these Public instances. There is also another instance which was not mentioned in before link.