The funds in our "Magnificent Retirement Mutual Funds" list are some of the top-performing, best managed funds available. If you're already invested in them, congratulations! If you're not, don't worry - it's never too late to start getting the advantages of these outstanding funds for your retirement.The easiest, most reliable way to judge a mutual fund's quality over time is by analyzing its performance, diversification, and fees. Our Zacks Rank 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.Let's break down some of the mutual funds with the highest Zacks Rank and the lowest fees.If you are looking to diversify your portfolio, consider Victory RS Global Growth R (RGGKX). RGGKX is a Global - Equity mutual fund. These funds invest in large markets like the U.S., Europe, and Japan, and operate with very few geographical limitations. This fund is a winner, boasting an expense ratio of 1.1%, management fee of 0.8%, and a five-year annualized return track record of 12.92%.VY T. Rowe Price Diversified Mid Cap Growth S2 (IAXTX): 1.17% expense ratio and 0.74% management fee. IAXTX is a Mid Cap Growth mutual fund. These funds aim to target companies with a market capitalization between $2 billion and $10 billion that are also expected to exhibit more extensive growth opportunities for investors than their peers. IAXTX, with annual returns of 11.33% over the last five years, is a well-diversified fund with a long track record of success.Fidelity Select Technology (FSPTX): 0.71% expense ratio and 0.54% management fee. With a much more diversified approach, FSPTX--part of the Sector - Tech mutual fund category--gives investors a way to own a stake in the notoriously risky tech sector. With a five-year annual return of 22.89%, this fund is a well-diversified fund with a long track record of success.There you have it. If your financial advisor had you put your money into any of our "Magnificent Retirement Mutual Funds," then they've got you covered. If not, you may need to talk.Do You Know the Top 9 Retirement Investing Mistakes?Investing in underperforming mutual funds is just one of the key errors that can derail your retirement plans.To learn more, read our just-released report: 9 Retirement Mistakes You Need to Avoid.This report can help you sidestep these costly mistakes and potentially achieve your retirement goals. Get Your FREE Guide Now Get Your Free (FSPTX): Fund Analysis Report Get Your Free (IAXTX): Fund Analysis Report Get Your Free (RGGKX): Fund Analysis Report To read this article on Zacks.com click here. Zacks Investment Research