Can a plan be self-directed?

Even though most companies will invest plan assets in stocks, bonds and mutual funds (what I would call qualifying assets), you do have the ability to invest in other non-qualified investments. This would include real estate, precious metals and gold, mortgages or hard money loans, bitcoin/other cryptocurrencies and even partnership units and private placements. So you have plenty of options.

However, these types of investments present a lot of challenges to the plan. So I would do these types of investments first in an IRA with the next option being a 401(k).