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.

Neuberger Berman Social Responsible R3 (NRARX): 1.28% expense ratio and 0.75% management fee. NRARX is a part of the Large Cap Value category, and invests in equities with a market capitalization of $10 billion or more, but whose share prices do not reflect their intrinsic value. NRARX has achieved five-year annual returns of an astounding 12.8%.

Invesco Technology Fund R5 (FTPIX Quick QuoteFTPIX - Free Report) . Expense ratio: 0.72%. Management fee: 0.6%. FTPIX is a Sector - Tech mutual fund, allowing investors to own a stake in a notoriously volatile sector with a much more diversified approach. This fund has managed to produce a robust 12.46% over the last five years.

American Funds Growth Fund of America F2 (GFFFX) is an attractive large-cap allocation. GFFFX 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. GFFFX has an expense ratio of 0.4%, management fee of 0.25%, and annual returns of 10.71% over the past 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.