Hi Brandon,
I'd recommend some other aggressive cichlids. How about a Jack dempsey? You can try a green terror, even maybe a red devil, but he should probably be couple inches smaller than the oscars. Do you have any fish you had in mind, that you liked? Rule of thumb is don't get something that your oscar can fit in his mouth

And don't get a bigger more aggressive fish. Oscars are relatively peacefull compared to red-devils, terrors etc...
Joe
Cichlidfish.com