We need balloon weights but they always come in multi packs.This means we are always left with the yellow ones.
So if someone could make a star shaped weight of at least 8g in pink or blue you will make millions.
The other weight manufacturers will hate you for breaking ranks but tough for them.

Why no love for the yellow?

I know of a small trade moulder that could make you what you want. Tooling costs may prohibitive though, because it would be a custom tool made for you. And a minimum order quantity to justify the tool and colour change.

Let me know if your serious.

Don’t know what a balloon weight is but why not contact one of the existing manufacturers and ask to supply only the ones you want. If the quantity is enough they will do it, if not it’s likely that a new mould from elsewhere is not viable.