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.

Goldman Sachs Small Cap Equity Insights R (GDSRX): 1.45% expense ratio and 0.8% management fee. GDSRX is a Small Cap Blend mutual fund, and usually targets stocks with market caps of less than $2 billion, letting investors diversify their funds among other kinds of small-cap equities. GDSRX has achieved five-year annual returns of an astounding 10.1%.

Brandes Emerging Markets Value R6 (BEMRX Quick QuoteBEMRX - Free Report) : 0.97% expense ratio and 0.95% management fee. BEMRX is a Non US - Equity option, focusing their investments acoss emerging and developed markets, and can often extend across cap levels too. BEMRX, with annual returns of 12.19% over the last five years, is a well-diversified fund with a long track record of success.

Steward International Enhanced Index I (SNTCX): 0.71% expense ratio and 0.37% management fee. SNTCX 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. The fund is mainly invested in equities, has a long reputation of salutary performance, and has yearly returns of 10.44% 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.