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.

How can you tell a good mutual fund from a bad one? It's pretty basic: if the fund is diversified, has low fees, and shows strong performance, it's a keeper. Of course, there's a wide range, but using the Zacks Mutual Fund Rank, we've found three mutual funds that would be great additions to any long-term investors' portfolios.

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

American Funds Fundamental Investors R1 (RFNAX): 1.36% expense ratio and 0.24% management fee. RFNAX 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. With annual returns of 11.25% over the last five years, this fund is a winner.

Columbia Global Technology Growth Z (CMTFX Quick QuoteCMTFX - Free Report) : 0.91% expense ratio and 0.79% management fee. CMTFX is a Sector - Tech mutual fund, allowing investors to own a stake in a notoriously volatile sector with a much more diversified approach. CMTFX, with annual returns of 13.88% over the last five years, is a well-diversified fund with a long track record of success.

LSV Emerging Markets Equity Inv (LVAZX): 1.2% expense ratio and 1% management fee. LVAZX is a Non US - Equity fund. Many of these funds like to allocate across emerging and developed markets, and will often focus on all cap levels. The fund is mainly invested in equities, has a long reputation of salutary performance, and has yearly returns of 12.29% over the last five years.

There you have it. If your financial advisor had you put your money into any of our top-ranked funds, then they've got you covered. If not, you may need to talk.