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.

Nuveen Global Equity Income I (NQGIX Quick QuoteNQGIX - Free Report) : 0.86% expense ratio and 0.71% management fee. NQGIX is a Global - Equity mutual fund investing in bigger markets like the U.S., Europe, and Japan; these kinds of funds aren't limited by geography. With annual returns of 14.54% over the last five years, this fund is a winner.

Principal Strategic Asset Management Conservative Growth C (SCGPX): 1.37% expense ratio and 0.28% management fee. SCGPX is classified as an Allocation Balanced fund, which seeks to invest in a balance of asset types, like stocks, bonds, and cash, and including precious metals or commodities is not unusual. With yearly returns of 10.04% over the last five years, SCGPX is an effectively diversified fund with a long reputation of solidly positive performance.

Columbia Select Large-Cap Value R (SLVRX) is an attractive large-cap allocation. SLVRX 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. SLVRX has an expense ratio of 1.05%, management fee of 0.67%, and annual returns of 14.87% over the past 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.