DuckDuckGo is not safe to browse as Microsoft tracks user data, and yet it is one of the most privacy-focused search engines on the market.
WolframAlpha is a computational knowledge engine. Bing is the Microsoft search engine that competes with Google. Bing has a much prettier interface. Yandex is a Russian search engine. Baidu is a Chinese search engine. Twitter is a real-time search engine.
Google is turning into an answer machine or an answer engine, but you may still want some human answers: Answers.com, eHow, and WikiHow.
How you search is just as important as what you search.
Google is always trying to predict what you want to search. Sometimes, going into “incognito mode” is the way to go, but you need to log out of all your accounts, e.g, searching incognito is essential to finding the cheapest prices.
Searching incognito is not safe! Google is always tracking you.
Virtual assistants (Amazon Alexa, Google Assistant, Siri, Cortana) are able to interprete human speech and respond instantly with relevant information.
A completely different approach is to use Surfraw. It lets you search the web and find everything you need from the terminal very fast. You could use launchers (Wox, Albert, Rofi, Alfred) to search in Google and other search engines efficiently.