It is never too late to invest in mutual funds for retirement. As such, if you plan to invest in some of the best funds, the Zacks Mutual Fund Rank can provide you with valuable guidance.The easiest way to judge a mutual fund's quality over time is by analyzing its performance, diversification, and fees. Using the Zacks Mutual Fund Rank of over 19,000 mutual funds, we've identified three outstanding mutual funds that are ideally suited to help long-term investors pursue and achieve their retirement investing goals.Here are the funds that have achieved the Zacks Mutual Fund Rank #1 (Strong Buy) and have low fees.BNY Mellon Natural Resources I (DLDRX): 0.91% expense ratio and 0.75% management fee. DLDRX is a Sector - Energy mutual fund, which encompasses a wide range of vastly changing and vitally important industries throughout this massive global sector. With annual returns of 15.46% over the last five years, this fund is a winner.Oak Ridge Dividend Growth I (ORDNX): 0.99% expense ratio and 0.75% management fee. ORDNX is a Large Cap Blend fund, targeting companies with market caps of over $10 billion. These funds offer investors a stability, and are perfect for people with a "buy and hold" mindset. ORDNX, with annual returns of 10.19% over the last five years, is a well-diversified fund with a long track record of success.Principal Blue Chip Fund I (PBCKX). Expense ratio: 0.65%. Management fee: 0.59%. Five year annual return: 11.39%. PBCKX is a part of the Large Cap Growth mutual fund category, which invest in many large U.S. companies that are expected to grow much faster compared to other large-cap stocks.There you have it. If your financial advisor had you put your money into any of our top-ranked funds, then they've got you covered. If not, you may need to talk. Zacks Names "Single Best Pick to Double" From thousands of stocks, 5 Zacks experts each have chosen their favorite to skyrocket +100% or more in months to come. From those 5, Director of Research Sheraz Mian hand-picks one to have the most explosive upside of all. It’s a little-known chemical company that’s up 65% over last year, yet still dirt cheap. With unrelenting demand, soaring 2022 earnings estimates, and $1.5 billion for repurchasing shares, retail investors could jump in at any time. This company could rival or surpass other recent Zacks’ Stocks Set to Double like Boston Beer Company which shot up +143.0% in little more than 9 months and NVIDIA which boomed +175.9% in one year.Free: See Our Top Stock and 4 Runners Up >>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 Get Your Free (DLDRX): Fund Analysis Report Get Your Free (PBCKX): Fund Analysis Report Get Your Free (ORDNX): Fund Analysis ReportTo read this article on Zacks.com click here.Zacks Investment Research