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.Looking at the history of these trends, perhaps none is more beloved than value investing. This strategy simply looks to identify companies that are being undervalued by the broader market. Value investors use fundamental analysis and traditional valuation metrics to find stocks that they believe are being undervalued by the market at large.Luckily, Zacks has developed its own Style Scores system in an effort to find stocks with specific traits. Value investors will be interested in the system's "Value" category. Stocks with both "A" grades in the Value category and high Zacks Ranks are among the strongest value stocks on the market right now.LyondellBasell (LYB) is a stock many investors are watching right now. LYB is currently sporting a Zacks Rank of #2 (Buy), as well as an A grade for Value. The stock has a Forward P/E ratio of 9.06. This compares to its industry's average Forward P/E of 20.59. Over the past 52 weeks, LYB's Forward P/E has been as high as 12.97 and as low as 5.27, with a median of 10.78.Investors should also note that LYB holds a PEG ratio of 1.13. This popular metric is similar to the widely-known P/E ratio, with the difference being that the PEG ratio also takes into account the company's expected earnings growth rate. LYB's industry currently sports an average PEG of 3.18. Over the last 12 months, LYB's PEG has been as high as 1.91 and as low as 0.77, with a median of 1.52.These are just a handful of the figures considered in LyondellBasell's great Value grade. Still, they help show that the stock is likely being undervalued at the moment. Add this to the strength of its earnings outlook, and we can clearly see that LYB is an impressive value stock right now.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 LyondellBasell Industries N.V. (LYB): Free Stock Analysis Report To read this article on Zacks.com click here.