Yellow Badass wristband
Yellow Awareness ribbons have been known to represent the following causes, but is not limited to this list.
Bladder Cancer - (Also see: Purple, Blue and Marigold ribbon below)
Bone cancer / Osteosarcoma
Craniofacial Acceptance (CCAKids.org)
Suicide Prevention (Also see Blue/Purple - Teal/Purple - Turquoise/Purple ribbon)