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.

Brown Advisory Flexible Equity Adviser (BAFAX Quick QuoteBAFAX - Free Report) : 0.93% expense ratio and 0.43% management fee. BAFAX is a part of the Allocation Balanced fund category; these funds like to invest in a variety of asset types, finding a balance between stocks, bonds, cash, and sometimes even precious metals and commodities; they are mostly categorized by their respective asset allocation. BAFAX has achieved five-year annual returns of an astounding 11.54%.

Janus Henderson Enterprise D (JANEX Quick QuoteJANEX - Free Report) . Expense ratio: 0.79%. Management fee: 0.64%. JANEX is a Mid Cap Growth mutual fund. These funds aim to target companies with a market capitalization between $2 billion and $10 billion that are also expected to exhibit more extensive growth opportunities for investors than their peers. This fund has managed to produce a robust 11.39% over the last five years.

T. Rowe Price New America Growth Adviser (PAWAX Quick QuotePAWAX - Free Report) . Expense ratio: 1.07%. Management fee: 0.63%. Five year annual return: 15.16%. PAWAX 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.

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.