Exactly, tons of options, but most of those fish will need a dedicated setup in this size tank, meaning they won't play nice together.There's a lot. You could get a kelberi in there (depending on the dimensions, if it's 6'x2' then you could do that), you could put some polypterus in there, eels, oscar, vieja, red devil, redfin pickerel, a haitian cichlid (again, depends on the dimensions), gulper catfish, most african cichlids, pike cichlid, mayan cichlid, wolf fish, bullhead catfish, etc.
I was thinking an Arowana, with 5 silver dollars, a pair of bichir, a pair red bay snook, and a pair of marble blue acara.Too many options you could go with here, unless you narrow it down to a category. That's a very versatile tank size, with the exception of fish that will physically outgrow it. Cichlids? Oddballs? Community? I'm very much into cichlids and there are many medium cichlids that you could have a pair of in there, if breeding was something you're interested in.