Generally speaking, which is taller, the frontal bone or the eyebrow bone?

If you are asking about the frontal bone and the brow bone, it is the same bone. Or, only the frontal bone, no eyebrow bone.

Protruding from the brow on the forehead is the eyebrow arch on the frontal bone, which is a structure on the frontal bone itself. When you say frontal bone, you may refer to another structure of frontal epiphysis, called frontal tubercle.

For most people, there is no significant difference in the prominence of these two structures.