I've been investing since I was 10 years old. I opened accounts at the top ten most popular brokerages in search of the very best custodian for my IRAs.

The best brokerage for IRAs is Fidelity. Fidelity is a world-class financial institution. Unlike Robinhood, Fidelity doesn't sacrifice functionality for excessive simplicity. Fidelity offers every type of financial account and access to almost every asset class.

If you started your investment journey using Cash App and Robinhood, that's fine. However, as you learn more, you will quickly outgrow Robinhood.

Fidelity is a brokerage for grownups. Once you start to explore what Fidelity has to offer, Robinhood will look like a joke in comparison.

As far as my knowledge goes in this matter, here are the following options for you:
Equity Trust Company offers both self-directed Roth and traditional IRAs. Low account fees start at $135 per year. Supports a wide variety of alternative investments like real estate, private companies, precious metals, etc. Over $25 billion in assets are under custody.

IRA Services Trust Company is another low-cost leader in self-directed IRAs. Annual fees start at $75 for basic custody services. Access to diverse alternative assets. Over $16 billion in retirement account assets were serviced.

Broad Financial offers competitive pricing with account fees ranging from $97 to $295 per year, depending on the services needed. Specializes in real estate IRAs but supports other assets too. Has over $8 billion in custodial account values.

Kingdom Trust Company: Account fees range from $100 to $250 based on the choice of service. Offers flexibility to invest in traditional as well as non-traditional assets. Does not charge transaction fees, which adds to the overall value.

New Direction IRA: Account setup fees start at $100 and annual fees start at $295. A wide menu of alternative investments supported, including private companies, startups, loans, tax liens, etc.