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 best way to shortlist great mutual funds is to ensure solid performance, diversification, and low fees. Some are better than others, but utilizing the Zacks Mutual Fund Rank, we have identified three mutual funds that could be solid additions to one's retirement portfolio.Let's take a look at some of our top-ranked mutual funds with the lowest fees.Fidelity Advisor Technology A (FADTX): 0.97% expense ratio and 0.52% management fee. FADTX is part of the Sector - Tech mutual fund category that invests in technology and lets investors own a stake in a notoriously volatile sector, but with a much more diversified approach. FADTX has achieved five-year annual returns of an astounding 13.74%.Lord Abbett Growth Leaders I (LGLIX): 0.66% expense ratio and 0.51% management fee. LGLIX is a Large Cap Growth option; these mutual funds purchase stakes in numerous large U.S. companies that are expected to develop and grow at a faster rate than other large-cap stocks. LGLIX, with annual returns of 11.87% over the last five years, is a well-diversified fund with a long track record of success.Virtus KAR Small-Cap Core I (PKSFX): 0.99% expense ratio and 0.75% management fee. PKSFX is a Small Cap Blend mutual fund, allowing investors a way to diversify their funds among various types of small-cap stocks. The fund is mainly invested in equities, has a long reputation of salutary performance, and has yearly returns of 13.84% over the last five years.These examples highlight the fact that there are some astonishingly good mutual funds out there. If your advisor has you in the good ones, bravo! If not, you may need to have a 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 (FADTX): Fund Analysis Report Get Your Free (PKSFX): Fund Analysis Report Get Your Free (LGLIX): Fund Analysis ReportTo read this article on Zacks.com click here.Zacks Investment Research