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.

Let's break down some of the mutual funds with the top Zacks Mutual Fund Rank and the lowest fees.

Victory Aggressive Growth (USAUX): 0.65% expense ratio and 0.42% management fee. USAUX 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. With annual returns of 12.22% over the last five years, this fund is a winner.

American Funds Cap World Growth & Income R4 (RWIEX) is a stand out amongst its peers. RWIEX is a Global - Equity mutual fund, which invests their assets in large markets, leveraging the global economy. With five-year annualized performance of 11.19%, expense ratio of 0.76% and management fee of 0.37%, this diversified fund is an attractive buy with a strong history of performance.

JPMorgan US Value R4 (JGRUX Quick QuoteJGRUX - Free Report) : 0.69% expense ratio and 0.4% management fee. JGRUX is a Large Cap Value mutual fund, which invests in stocks with a market cap of $10 billion of more, but whose share prices do not reflect their intrinsic value. With a five-year annual return of 13.56%, this fund is a well-diversified fund with a long track record of success.

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.