Simply put, almost anything can be owned by a trust.
Real estate, stocks and bonds, bank accounts, businesses, vehicles, boats, personal property, livestock, and so many more things.
But, there are a few that cannot be owned by a trust.
Retirement accounts (401k, 403b, IRA, Roth IRA, and similar plans) cannot be owned by a trust. The IRS requires that these accounts be owned by an individual, therefore they cannot be owned by a trust.
Certain professional businesses, such as doctors, lawyers, dentists, accountants, and real estate brokers also cannot be owned by a trust.