I have always heard them referred to as brackets.

Architectural brackets

They are usually on houses from the 20's and 30's around here. They support the barge or fly rafter and the roof overhang.

I would disagree that they have no purpose. Many houses here have sagging overhangs where the brackets have pulled away from the walls. Unless the overhang is less than 16 inches or so, they are needed to support the roof.