These funds could be poised for serious growth.Investing in exchange-traded funds (ETFs) can be a smart way to diversify your portfolio, gain exposure to a particular sector of the market, or own a small slice of the market as a whole. Growth ETFs, specifically, are designed to earn above-average returns over time, as they focus on stocks with higher growth potential. Because you're investing in many stocks at once through an ETF, that can help limit risk while still capitalizing on growth companies.While t ...