What happens to my H-1B if I work freelance on my free time?

Your H1B status allows you to work for your H1B employer only. Thus, the freelance work could be considered as an unauthorized employment, and you will be in violation of your H1B status.

Generally, the H-1B visa doesn't allow for the beneficiary of it (you) to engage in employment for any entity, including for yourself, other than the petitioner (H-1B sponsor), but there are alternatives like amending the H-1B petition or changing status to an O-1 visa, assuming you qualify, through a filing agent (Azadi Law P.A. offers this), which allows you to work for more than one entity.

H-1B visa holders are authorized to work only for the sponsoring employer and in the specific role outlined in the approved petition. Any employment outside this scope, including freelance work, is considered unauthorized.
Before engaging in any freelance or additional work, consult with an immigration attorney to explore legal avenues or other visa options that may accommodate your goals.

You may not perform freelance work outside of your H-1B employment unless each independent client or project sponsor files a separate H-1B petition on your behalf.

You can only work within the scope of your H-1B for that employer. However, you can get a simultaneous part time H-1B to work for a second employer. Please call my office for a consultation if you would like a deeper strategy.

No, H-1B must work for the sponsoring employer. Freelance works can mean working as an independent contractor or maybe for another employer, which is not allowed.

I suggest a concurrent H-1B for this endeavor if the job description will qualify. Otherwise it would be unauthorized employment.