Our "Magnificent Retirement Mutual Funds" list includes some of the best managed and best performing funds around. If you're already invested in these, congratulations! But if you're just now discovering them, don't worry. When it comes to your retirement, it's never too late to start investing in the best.

How can you tell a good mutual fund from a bad one? It's pretty basic: if the fund is diversified, has low fees, and shows strong performance, it's a keeper. Of course, there's a wide range, but using our Zacks Rank, we've found three mutual funds that would be great additions to any long-term retirement investors' portfolios.

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

Janus Henderson Global Technology T (JAGTX - Free Report) has a 0.93% expense ratio and 0.64% management fee. With a much more diversified approach, JAGTX--part of the Sector - Tech mutual fund category--gives investors a way to own a stake in the notoriously risky tech sector. With yearly returns of 18.71% over the last five years, this fund clearly wins.

ClearBridge Small Cap Growth I (SBPYX - Free Report) is a stand out amongst its peers. SBPYX is one of many Small Cap Growth mutual funds; these funds tend to create their portfolios around stocks with market capitalization of less than $2 billion. With five-year annualized performance of 11.06%, expense ratio of 0.91% and management fee of 0.75%, this diversified fund is an attractive buy with a strong history of performance.

Fidelity Advisor Growth Opportunit (FAOFX - Free Report). Expense ratio: 0.01%. Management fee: 0%. Five year annual return: 16.82%. FAOFX is a part of the Large Cap Growth mutual fund category, which invest in many large U.S. companies that are expected to grow much faster compared to other large-cap stocks.

So, there you have it - if your advisor has you invested in any of our "Magnificent Retirement Mutual Funds," they are certainly earning their keep. If not, you may want to look elsewhere.