While the proven Zacks Rank places an emphasis on earnings estimates and estimate revisions to find strong stocks, we also know that investors tend to develop their own individual strategies. With this in mind, we are always looking at value, growth, and momentum trends to discover great companies.Of these, value investing is easily one of the most popular ways to find great stocks in any market environment. Value investors use tried-and-true metrics and fundamental analysis to find companies that they believe are undervalued at their current share price levels.In addition to the Zacks Rank, investors looking for stocks with specific traits can utilize our Style Scores system. Of course, value investors will be most interested in the system's "Value" category. Stocks with "A" grades for Value and high Zacks Ranks are among the best value stocks available at any given moment.One company to watch right now is Energy Transfer LP (ET). ET is currently sporting a Zacks Rank of #1 (Strong Buy) and an A for Value. The stock has a Forward P/E ratio of 6.02. This compares to its industry's average Forward P/E of 9.38. Over the past 52 weeks, ET's Forward P/E has been as high as 11.13 and as low as 4.50, with a median of 7.15.Another notable valuation metric for ET is its P/B ratio of 0.76. Investors use the P/B ratio to look at a stock's market value versus its book value, which is defined as total assets minus total liabilities. This company's current P/B looks solid when compared to its industry's average P/B of 1.30. ET's P/B has been as high as 0.90 and as low as 0.44, with a median of 0.58, over the past year.Finally, we should also recognize that ET has a P/CF ratio of 3.61. This data point considers a firm's operating cash flow and is frequently used to find companies that are undervalued when considering their solid cash outlook. This company's current P/CF looks solid when compared to its industry's average P/CF of 6.07. Within the past 12 months, ET's P/CF has been as high as 7.64 and as low as 2.87, with a median of 4.20.These figures are just a handful of the metrics value investors tend to look at, but they help show that Energy Transfer LP is likely being undervalued right now. Considering this, as well as the strength of its earnings outlook, ET feels like a great value stock at the moment. Zacks' Top Picks to Cash in on Artificial Intelligence In 2021, this world-changing technology is projected to generate $327.5 billion in revenue. Now Shark Tank star and billionaire investor Mark Cuban says AI will create "the world's first trillionaires." Zacks' urgent special report reveals 3 AI picks investors need to know about today.See 3 Artificial Intelligence Stocks With Extreme Upside Potential>>Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report Energy Transfer LP (ET): Free Stock Analysis Report To read this article on Zacks.com click here.