Carbon-Ti makes a full spectrum of chainrings for road and mountain bikes. The big rings have an aluminum tooth section on a carbon spider and come in around 50g to 60g depending on size. The Ti MTB big rings are about 60g, also, but the grannies are 25g to 28g.
Prices range from €220 for the carbon/alloy big rings down to €150 for the full titanium big rings to €40 for the Ti granny gears. Detail pic after the break…