None beyond that ISO standard, which yes, is advisory. If it can be shown to be dangerously unsafe, it's subject to a recall, but that's only going to happen if the batteries tend to explode or something like that. There's lots of unsafe types of plastic that get through.

https://www.compliancegate.com/sex-toys-regulations-united-states/

The United States Consumer Product Safety Commission (CPSC) is an independent agency of the US government, overseeing the safety of consumer products. It develops and enforces safety standards in the United States. It also conducts research related to hazards and risks to the public caused by consumer products.

The CPSC has not yet developed a specific safety standard for sex toys. However, importers and manufacturers are required to report to the CPSC if their product could create a substantial risk of injury to the public, for example, because of a manufacturing defect or a design issue.

In practice, an unsafe sex toy is subject to a recall, regardless of whether it is covered by mandatory safety standards. Hence, importers or manufacturers of sex toys should ensure that their products are safe, for instance by complying with relevant voluntary safety standards.