Have you known that WinClicks.io has a Keyword tracker Intersection tool?
That allows you to compare multiple products and identify "overlapping" words?!
You can also exclude irrelevant words from the results or follow to new words using the "+ word" or "- word" function. You can sort words by “Search Volume” and “Units sold” filters to eliminate redundancies. It's surprisingly easy, fast and effective.
Just go to the section “Intersection”, add competitors ASINs, click on the button “Confirm” and use all available data with pleasure.