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 easiest way to judge a mutual fund's quality over time is by analyzing its performance, diversification, and fees. Using the Zacks Mutual Fund Rank of over 19,000 mutual funds, we've identified three outstanding mutual funds that are ideally suited to help long-term investors pursue and achieve their retirement investing goals.

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

PGIM Jennison Mid-Cap Growth A (PEEAX Quick QuotePEEAX - Free Report) : 1.07% expense ratio and 0.57% management fee. PEEAX is a Mid Cap Growth mutual fund. These mutual funds choose companies with a stock market valuation between $2 billion and $10 billion. PEEAX has achieved five-year annual returns of an astounding 12.37%.

Putnam Small Cap Value R (PSCRX Quick QuotePSCRX - Free Report) is a stand out amongst its peers. PSCRX is a Small Cap Value mutual fund option, which typically invest in companies with market caps under $2 billion. With five-year annualized performance of 10.08%, expense ratio of 0.72% and management fee of 0.62%, this diversified fund is an attractive buy with a strong history of performance.

Vanguard Selected Value Fund (VASVX Quick QuoteVASVX - Free Report) : 0.43% expense ratio and 0.37% management fee. VASVX is a Mid Cap Value mutual funds that aims to target medium-sized companies that possess strong value and income opportunities for investors. With a five-year annual return of 12.41%, this fund is a well-diversified fund with a long track record of success.

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.