I'm going to try to completely vent myself of Paper Mario hype so I'm not disappointed when he's deconfirmed. Here, then, is a complete moveset I drew up for him.
(Doing this really made me appreciate how much work and creativity Sakurai & co. put into this game. Trying to come up with a full set of appropriate, unique moves isn't easy; some of these, I admit, are real stretches.)
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Paper Mario's special attacks are all based on his partners.
Neutral B: Mario kicks out Kooper's shell, which slides forward a few feet and then comes back to him.
Side B: Mario drops Admiral Bobbery, who takes a few steps forward, stops for a second, and explodes. He can be detonated at any time by pressing B. Once he explodes, he flies up into the air, and Paper Mario has to wait for him to drop back down before he can use him again.
Down B: Vivian pulls Mario into the shadows for a second, causing all attacks to miss. -OR- Flurry blows a gust of wind, pushing any character or item back (much like FLUDD, but Flurry can keep it up longer.)
Up B: Parakarry grabs Mario and flies him back onto the stage. Works like Snake's Cypher.
A: Mario swings his hammer down.
A combo: Two swings down followed by a side swing which knocks opponents back.
Dash Attack: Speedy Spin - Mario whirls around. This is the spin move you can use in the field in Paper Mario.
Paper Mario's tilts are taken from Sticker Star.
Forward Tilt: Sombrero - Mario throws a sombrero a very short distance.
Down Tilt: Snowball - Mario drops a big snowball in front of him, which explodes, damaging anyone on either side of him.
Up Tilt: Spike Helmet - Mario dons a helmet with a sharp point which pokes opponents.
Paper Mario's smash attacks are badged-derived hammer moves.
Forward Smash: Fire Drive - Mario uses his hammer to knock a fireball forward. Once it hits the ground, the fireball travels a short distance along the ground, burning anything in its path. The longer you charge it, the bigger the fireball.
Down Smash: Ice Smash - Mario brings his hammer down in a shower of snowflakes. When fully charged, it freezes your opponent.
Up Smash: Hammer Throw - Mario chucks his hammer in a high arc. It flies until hit hits a something (character, item, stage,) at which point it dissipates, or until it falls off the stage. The longer you charge it, the farther it flies.
Paper Mario's aerials are various badge-derived moves (I didn't think there were enough suitable jump moves for a full complement of aerials.)
Forward Air: Piercing Blow - In the Paper Mario games, Piercing Blow is a hammer move that cuts through enemies' defenses. Here, it does a lot of damage but has no knockback (i.e., your opponent won't even flinch when hit.)
Back Air: Zap Tap - Mario momentarily charges himself with electricity, shocking anyone who touches him.
Down Air: Sleepy Stomp - Mario kicks downward. When sweetspotted, it puts opponents to sleep and causes little sheep to appear.
Up Air: Tornado Jump - a tornado appears under Mario, whirling him upward. Both the spinning Mario and the tornado itself do damage.
Paper Mario's grabs use Pixls.
Grab: Mario throws Thoreau forward. Roughly the range of Lucas' snake.
Pummel: Cudgel bops the opponent.
Forward Throw: Dashell speeds across the screen and tackles the opponent.
Back Throw: Basically the same as f-throw. Like regular Mario's throws, the f-throw is faster, but it doesn't send opponents as far.
Down Throw: Thudley squishes the opponent.
Up Throw: Carrie appears underneath the opponent and lifts them up. The more damage the opponent has, the farther Carrie flies.
Final Smash: Earth Tremor - The Diamond Star's move from TTYD. Mario hops aboard the Crystal Star, a meter appears on the screen, and you must hit A with proper timing to power up the star. The star then bounces up and down, sending shockwaves across the screen. The more you powered it up, the bigger the shockwaves (if you missed every prompt, then you get no shockwaves, because that's just sad.)
Side Taunt: Mario rifles through his sticker album, littering the ground with flashy stickers.
Down Taunt: Mario folds himself into either a paper boat or a paper plane.
Up Taunt: The Seven Star Spirits circle around Mario, showering him in sparkles.