Yeah, and traveling Matt spreads his arms out that way, too. "Behold! Traveling Matt has come home!"
The big teams seemed to be Jim and Frank, Jerry and Richard, Dave and Steve, and Kathy and Karen. But we've seen plenty of other on-screen teams, like Jerry and Steve, or Richard and Kathy.
Let's see...well, we know all about Richard's head-tilt and nod. And if one of Richard's characters is trying to understand something, or is uncertain, that character tends to look down at the floor while tilting its head from side to side a little bit.
Jim's characters tend to quickly pivot their heads from side to side when they laugh. And if Jim's playing a live-hand Muppet like Rowlf or Cantus, he raises his left hand a bit when he's philosophizing.
(all this is proof that we've been watching the Muppets way too much
)