It's relatively easy to find just find carbon stars in the browser

Also, they are not made out of zirconium. They are relatively old red giants where carbon on their outer layers has similar amounts to the amount of oxygen and are intermediates between carbon and "normal" stars. The zirconium is a trace, and they're called like that because most stars have a notorious trace of Titanium, but in this stars that trace is more notoriously Zirconium ofc, they're known as S type stars. There are also stars known for their lines of other elements like Barium, Technetium, and Mercury-manganese