BibleHub is great for looking at Scriptures and seeing the actual Hebrew / Greek words (Interlinear). BibleGateway is great because I know how to use it for parallel translations in the verse listings. But I just found this:

Bible.Knowing-Jesus.com

This seems to be an ideal place to search for a word in the Bible because it searches in about a dozen translations at once and presents the results grouped together with handy and helpful side bars on the right side of the results page!

Example:

=> bible.knowing-jesus.com/words/Attentive