There is never a wrong time to invest in mutual funds for retirement. So, if you're still looking for the best mutual funds, the Zacks Mutual Fund Rank can be a great guide.

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.

Wells Fargo Disciplined US Core Admiral (EVSYX Quick QuoteEVSYX - Free Report) : 0.78% expense ratio and 0.35% management fee. EVSYX 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. With annual returns of 10.42% over the last five years, this fund is a winner.

Nationwide Growth Fund A (NMFAX Quick QuoteNMFAX - Free Report) : 0.81% expense ratio and 0.45% management fee. NMFAX 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. NMFAX, with annual returns of 12.63% over the last five years, is a well-diversified fund with a long track record of success.

BNY Mellon Natural Resources I (DLDRX Quick QuoteDLDRX - Free Report) . Expense ratio: 0.91%. Management fee: 0.75%. Five year annual return: 15.66%. DLDRX is a Sector - Energy mutual fund, which encompasses a wide range of vastly changing and vitally important industries throughout this massive global sector.

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.