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.

Timothy Plan Aggressive Growth I (TIAGX) has a 1.35% expense ratio and 0.85% management fee. TIAGX is a Mid Cap Growth mutual fund. Mid Cap Growth funds pick stocks--usually companies with a market cap between $2 billion and $10 billion--that demonstrate extensive growth opportunities for investors compared to their peers. With yearly returns of 15.14% over the last five years, this fund clearly wins.

Ave Maria Value Focused (AVERX Quick QuoteAVERX - Free Report) is a stand out amongst its peers. AVERX is a Small Cap Value fund, and these funds are known for investing in companies with market caps under $2 billion. With five-year annualized performance of 15.37%, expense ratio of 1.03% and management fee of 0.75%, this diversified fund is an attractive buy with a strong history of performance.

First Eagle Overseas R6 (FEORX) is an attractive large-cap allocation. FEORX is a part of the Non US - Equity fund category, many of which will focus across all cap levels, and will typically allocate their investments between emerging and developed markets. FEORX has an expense ratio of 0.79%, management fee of 0.75%, and annual returns of 10.2% 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.