Ti Bolts...(The bolts, not the bikes...)

[FluffyChicken]

ebay from china. They have a lot of pretty colors. FYI disc brake bolts will also work for bottle cages.

Haha I 3d printed the bolts for bottle cage holes etc, even the granny spacers. In low strength PLA, does the job, light weight, no corrosion too. Not for your disc brakes though ;-)

Back on topic, Pro-Bolt above has been linked many times over the years. If you want quality and a guarantee it'll be excellent...

Other than that random AliExpress etc.