Can anyone think of their own Hammer Bros? Just not using hammers. Here are mine.
Thunder Bros: Shoots electricity from their hands
Axe Bros: Toss and/or throws Hand Axes.
How about Shuriken Bros. They throw a series of shuriken at you, usually three at a time making it more difficult to avoid. They also can target you specifically so you have to wait for them to throw before you jump to avoid them.