Investing in mutual funds for retirement is never too late. And the Zacks Mutual Fund Rank can be an excellent tool for investors looking to invest in the best funds.How can you tell a good mutual fund from a bad one? It's pretty basic: if the fund is diversified, has low fees, and shows strong performance, it's a keeper. Of course, there's a wide range, but using the Zacks Mutual Fund Rank, we've found three mutual funds that would be great additions to any long-term retirement investors' portfolios.Let's take a look at some of our top-ranked mutual funds with the lowest fees.DFA US Core Equity 1 I (DFEOX): 0.14% expense ratio and 0.12% management fee. DFEOX is part of the Large Cap Blend section, and these mutual funds most often invest in firms with a market capitalization of $10 billion or more. By investing in bigger companies, these funds offer more stability, and are often well-suited for investors with a "buy and hold" mindset. DFEOX has achieved five-year annual returns of an astounding 10.99%.Janus Henderson Global Technology Institutional (JGLTX). Expense ratio: 0.72%. Management fee: 0.64%. With a much more diversified approach, JGLTX--part of the Sector - Tech mutual fund category--gives investors a way to own a stake in the notoriously risky tech sector. This fund has managed to produce a robust 14.45% over the last five years.T. Rowe Price New Amer Growth I (PNAIX): 0.66% expense ratio and 0.63% management fee. PNAIX is a Large Cap Growth mutual fund, and these funds invest in many large U.S. firms that are projected to grow at a faster rate than their large-cap peers. With a five-year annual return of 15.62%, this fund is a well-diversified fund with a long track record of success.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. Just Released: Free Report Reveals Little-Known Strategies to Help Profit from the $30 Trillion Metaverse Boom It's undeniable. The metaverse is gaining steam every day. Just follow the money. Google. Microsoft. Adobe. Nike. Facebook even rebranded itself as Meta because Mark Zuckerberg believes the metaverse is the next iteration of the internet. The inevitable result? Many investors will get rich as the metaverse evolves. What do they know that you don't? They’re aware of the companies best poised to grow as the metaverse does. And in a new FREE report, Zacks is revealing those stocks to you. This week, you can download, The Metaverse - What is it? And How to Profit with These 5 Pioneering Stocks. It reveals specific stocks set to skyrocket as this emerging technology develops and expands. Don't miss your chance to access it for free with no obligation.>>Show me how I could profit from the metaverse!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 (DFEOX): Fund Analysis Report Get Your Free (PNAIX): Fund Analysis Report Get Your Free (JGLTX): Fund Analysis Report To read this article on Zacks.com click here. Zacks Investment Research