The Awesome Threesome is a trio of supervillains that first appeared in Aquaman #36 (September 1967). The team is comprised of Torpedoman, Claw, and Magneto.
Torpedoman also appeared in the Aquaman cartoon episode "Treacherous is the Torpedoman", which debuted in October 1967. He returned in the November 1967 episode "The Torp, The Magneto, and The Claw", which featured the debuts of Claw and Magneto (obviously).
So why are these on this site? They clearly showed up in comics before animation. Well, not so fast. First, both of these episodes and the issue were written by Bob Haney. Furthermore, we've seen several times before that the lead time for animation can cause characters created for animation to jump over to comics before the animation airs. And beyond that, check out the cover to Aquaman #36.
It's the only issue to feature that banner at the top, so I'm pretty sure this issue was meant to promote the cartoon by featuring characters created for the cartoon. I think that also holds true for Tusky the Walrus, as seen last week.