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 break down some of the mutual funds with the top Zacks Mutual Fund Rank and the lowest fees.

If you are looking to diversify your portfolio, consider Janus Henderson Enterprise S (JGRTX Quick QuoteJGRTX - Free Report) . JGRTX is a Mid Cap Growth mutual fund. These mutual funds choose companies with a stock market valuation between $2 billion and $10 billion. This fund is a winner, boasting an expense ratio of 1.16%, management fee of 0.64%, and a five-year annualized return track record of 10.67%.

Great-West Loomis Sayles Small Cap Value (MXLSX Quick QuoteMXLSX - Free Report) : 1.09% expense ratio and 0.71% management fee. MXLSX is categorized as an All Cap Value fund, and like the name suggests, invests across the cap spectrum in small-cap, mid-cap, and large-cap companies. MXLSX, with annual returns of 10.98% over the last five years, is a well-diversified fund with a long track record of success.

Ivy Large Cap Growth Y (WLGYX Quick QuoteWLGYX - Free Report) . Expense ratio: 0.89%. Management fee: 0.61%. Five year annual return: 17.11%. WLGYX 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.

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.