The individual route is designed for exactly that situation, subject to vetting, the gift and the EB-1 or EB-2 conditions. No sponsor is required, but no ordinary visa eligibility is created by the payment either.
No employer needed, but the immigrant category still applies
Under the official framework an individual may apply without a corporate sponsor by paying the US$15,000 nonrefundable processing fee, passing vetting and then making the US$1,000,000 gift to the U.S. government. The consultant does not need a job offer. He does, however, need to satisfy the eligibility of the employment-based category through which the case is processed, EB-1 or EB-2, remain admissible and have a visa number available. The Gold Card is therefore best understood as a route into an existing immigrant category with a financial condition attached, not as a category in its own right. The requirements should be checked against the official page at the time of application because the program is administered under an executive order and its terms can be revised. A consultant who cannot meet EB-1 or EB-2 standards should raise that before paying the fee.
A first review should distinguish the published Gold Card framework from familiar nonimmigrant categories. It describes a payment by the applicant to the U.S. government after required vetting; it is not a conventional visa and it is not an investment that creates a business-risk return. Retain current official terms with their publication date and confirm who may apply before arranging funds. Hypothetical example: an independent documentary editor is offered a corporate contribution but wants to remain the applicant. The written terms must show whether the applicant, rather than a sponsor, is the person who makes the required gift payment.