Genie History Search - Always find the page you are looking for, like magic.
WorldBrain (Re)search-Engine - Full-Text Search your Browsing History & Bookmarks
WhoisMind - Advanced reverse whois search inc.
Microsoft Web Activities - Microsoft's new extension bringing timeline to Chrome
Occamm - When you search for something on Occamm, it suggests keywords along with the results, which you can then select to refine your query further.It is especially helpful when you are researching something.And Occamm is completely privacy friendly.
Better History - Your Chrome Browsing history. Better.