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.

Fidelity Convertible Securities (FCVSX Quick QuoteFCVSX - Free Report) : 0.73% expense ratio and 0.51% management fee. FCVSX is a Convertible Bonds mutual fund, and these funds are unique in the fixed income world; these securities have components of both fixed income and equity, making them hybrid securities. FCVSX has achieved five-year annual returns of an astounding 11.26%.

Hood River Small Cap Growth Institutional (HRSMX Quick QuoteHRSMX - Free Report) : 1.06% expense ratio and 0.9% management fee. HRSMX is a Small Cap Growth mutual fund and tends to feature small companies in up-and-coming industries and markets. HRSMX, with annual returns of 12.6% over the last five years, is a well-diversified fund with a long track record of success.

Commerce Growth Fund (CFGRX Quick QuoteCFGRX - Free Report) . Expense ratio: 0.69%. Management fee: 0.4%. Five year annual return: 11.59%. CFGRX 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.

We hope that your investment advisor (if you use one) has you invested in one or all of the top-ranked mutual funds we've reviewed. But if that isn't the case, it might be time to have a conversation or reconsider this vitally important relationship.