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.

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.

T. Rowe Price Blue Chip Growth Fund (TRBCX) has a 0.7% expense ratio and 0.55% management fee. TRBCX 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. With yearly returns of 10.14% over the last five years, this fund clearly wins.

American Century Global Gold Institutional (AGGNX Quick QuoteAGGNX - Free Report) . Expense ratio: 0.46%. Management fee: 0.45%. AGGNX is a Sector - Precious Metal mutual fund, typically investing in companies that are involved in the mining and production of precious metals like gold, silver, platinum, and palladium. This fund has managed to produce a robust 31.09% over the last five years.

PGIM QuantSolutions SmCap Value A (TSVAX). Expense ratio: 1.09%. Management fee: 0.6%. Five year annual return: 9.78%. TSVAX is a Small Cap Value mutual fund, investing in small companies with stock market valuation less than $2 billion.

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.