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.

Fidelity Convertible Securities (FCVSX Quick QuoteFCVSX - Free Report) has a 0.72% expense ratio and 0.55% management fee. FCVSX is a Convertible Bonds mutual fund, and these funds are unique in the fixed income world; these securities have components of both fixed income and equity, making them hybrid securities. With yearly returns of 11.38% over the last five years, this fund clearly wins.

Ivy Large Cap Growth I (IYGIX Quick QuoteIYGIX - Free Report) . Expense ratio: 0.64%. Management fee: 0.6%. IYGIX 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. This fund has managed to produce a robust 14.34% over the last five years.

Neuberger Berman Guardian Investor (NGUAX Quick QuoteNGUAX - Free Report) : 0.83% expense ratio and 0.74% management fee. NGUAX 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. The fund is mainly invested in equities, has a long reputation of salutary performance, and has yearly returns of 13.39% over the last five years.

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.