I know H frame from X frame, but what are the names of frames like the Tweaker and the Hellbender? In one I see flat out front arms and splayed backs, and more frog like front arms in others. I've heard "dead cat", but not sure which of these that would be.

I think they can be refered to as "Deadcat".

Deadcat and Reverse Deadcat are where either the front or rear arms are X-config and the other arms are H-config. Some know it as asymmetric spider-X. Reverse has the X arms at the front, like the UBAD Inversion, Tweaker. Normal deadcat is H-arms front config, like TBS Disco Pro. Google should explain most of these for you.

BUT! Some might argue that it's to do with the motor position rather than the shape/position of the arms. I call my frame as a deadcat but I have seen people say it's not, it's actually an H frame (wider than it is long). A true deadcat has all four arms the same length, but the front ones are rotated back further than the back ones, this means it's actually much wider in the front than it is at the back.

So it really depends on how you look at it.

I refer to all my quads as Roger, or "you stupid piece of Sh*t".