It is never too late to invest in mutual funds for retirement. As such, if you plan to invest in some of the best funds, the Zacks Mutual Fund Rank can provide you with valuable guidance.

The easiest, most reliable way to judge a mutual fund's quality over time is by analyzing its performance, diversification, and fees. The Zacks Mutual Fund Rank, which covers over 19,000 mutual funds, has helped us identify three outstanding options that are perfect for any long-term investors' portfolios that is retirement-focused.

Here are the funds that have achieved the Zacks Mutual Fund Rank #1 (Strong Buy) and have low fees.

If you are looking to diversify your portfolio, consider Voya Global Equity I (NAWIX). NAWIX is a Global - Equity mutual fund. These funds invest in large markets like the U.S., Europe, and Japan, and operate with very few geographical limitations This fund is a winner, boasting an expense ratio of 0.62%, management fee of 0.5%, and a five-year annualized return track record of 10.23%.

Fidelity Select Energy Portfolio (FSENX Quick QuoteFSENX - Free Report) : 0.64% expense ratio and 0.63% management fee. FSENX is a Sector - Energy mutual fund, which encompasses a wide range of vastly changing and vitally important industries throughout this massive global sector. With yearly returns of 23.92% over the last five years, FSENX is an effectively diversified fund with a long reputation of solidly positive performance.

AQR Emerging Multi Style II I (QTELX): 0.69% expense ratio and 0.5% management fee. QTELX is a part of the Non US - Equity fund category, many of which will focus across all cap levels, and will typically allocate their investments between emerging and developed markets. With a five-year annual return of 10.52%, this fund is a well-diversified fund with a long track record of success.

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.