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, most reliable way to judge a mutual fund's quality over time is by analyzing its performance, diversification, and fees. The Zacks Mutual Fund Rank, which covers over 19,000 mutual funds, has helped us identify three outstanding options that are perfect for any long-term investors' portfolios that is retirement-focused.

Here are the funds that have achieved the Zacks Mutual Fund Rank #1 (Strong Buy) and have low fees.

Victory Sycamore Established Value A (VETAX Quick QuoteVETAX - Free Report) : 0.9% expense ratio and 0.45% management fee. VETAX is a Mid Cap Value fund, which usually invests in companies with a stock market valuation between $2 billion and $10 billion. With annual returns of 12.19% over the last five years, this fund is a winner.

PGIM Jennison Small Company A (PGOAX Quick QuotePGOAX - Free Report) . Expense ratio: 1.15%. Management fee: 0.67%. PGOAX is a Small Cap Blend mutual fund that usually targets companies with a market capitalization of less than $2 billion. This fund has managed to produce a robust 10.9% over the last five years.

JPMorgan Intrepid Growth I (JPGSX Quick QuoteJPGSX - Free Report) : 0.59% expense ratio and 0.3% management fee. JPGSX 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. The fund is mainly invested in equities, has a long reputation of salutary performance, and has yearly returns of 16.76% 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.