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 learn about some of Zacks' highest ranked mutual funds with low fees you may want to consider.

Amana Growth Investor (AMAGX Quick QuoteAMAGX - Free Report) : 0.92% expense ratio and 0.62% management fee. AMAGX 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. AMAGX has achieved five-year annual returns of an astounding 13.86%.

BNY Mellon Appreciation Investor (DGAGX Quick QuoteDGAGX - Free Report) . Expense ratio: 0.88%. Management fee: 0.55%. DGAGX 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. This fund has managed to produce a robust 10.38% over the last five years.

T. Rowe Price Health Sciences I (THISX Quick QuoteTHISX - Free Report) : 0.67% expense ratio and 0.63% management fee. THISX is a Sector - Health mutual fund, which give investors an opportunity to focus on healthcare, one of the largest sectors of the American economy. The fund is mainly invested in equities, has a long reputation of salutary performance, and has yearly returns of 9.57% 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.