Thin wall glass hollow spheres

Your search terms might be unclear. Are you talking about something which is used in a lab? If so, then check catalogs for the closest thing and do searches based on that terminology, which is more likely to be standard or close to standard in the industry (and you can also hit the Contact page on any of those sites and just ask directly). Or you can try specialty stuff like glass blowers or even places that sell light fixtures.

E.g.

https://www.schaeferglas.com/products/glass-balls/