Wander completely dominating Lord Hater in a "Greatest in the Galaxy" contest.
And later, as Hater gets into a laser-firing fit in his ship after losing said contest, Wander and Sylvia make him crash his ship into his own statue by challenging him to a race for the title.
In "The Fugitives," Wander reunites a mother with her baby, saves a balloon man's life by picking up a tack, and prevents a war by dividing food equally between two ant armies...all in one day. And all that good karma gets paid in full when all the people Wander helped throughout the episode (including the garbage barge captain whom Wander helped tie his shoes) help Wander and Sylvia escape the planet.
Wander deflecting a missile aimed for a sun by jumping on it.
"Sylvia, six fingers!"
A subtle one at the end of "The Good Deed." After Lord Hater's ship gets blown up, he feebly asks Wander and Sylvia for help. The two walk backwards, even rewinding the song they're singing (just like at the beginning of the episode), stop next to Hater...and both calmly tell him "No." At first, this doesn't seem like much, but consider how in "The Fugitives," Wander nearly had a nervous breakdown when he was told not to help people. Now, just an episode later, he's able to calmly and definitively refuse to help someone who asks for it. Definitely a noticeable contrast.
In "The Troll", after the eponymous creature easily curb-stomps the Baaaaa-halla warriors to get his food sack, he approaches Wander who's resting in the same room (and oddly not helping like he usually does). The troll then starts throwing insults about Wander's appearance. What does Wander do? He simply ignores him, prompting Sylvia and the warriors to do the same, thus rendering the troll tiny and powerless.
From "The Box" we have Sylvia forcing the Lords of Illumination to put something in said box, due to it driving Wander up a wall all episode.
Sylvia: This whole thing was a set-up! There's nothing IN the box, is there?
Lord of Illumination: Yes, YES! You get it! Could you please help me explain to him?
(Wander continues to guess what's in the box)
Sylvia: LISTEN, YOU COSMIC CREEP!!!!! MY FRIEND HERE DOESN'T WANT YOUR "Greatest conciousness" HULLABALOO!!!! WHAT HEWANTSIS TO SEESOMETHING IN THE BOX!!!!!!!!! So, PUT. SOMETHING. IN. THE. BOX.
And her Screw This, I'm Outta Here! attitude once the Lord of Illumination make a "WE were the ones who needed learning speech" right after all the conflict is finally resolved.
In the "The Ball", They tried and failed to successfully preventing Buster, the Giant Space Dog to destroy/chew their planet, But Wander has an incredible and crazy idea by thinking instead to flee is to be fleas by living on Buster.
"The Bounty" has a few for Commander Peepers:
Getting the robot bounty hunter to teleport itself back to Lord Hater's ship
His awesome defeat of the potted plant
'The Picnic' has Lord Hater fling a dinosaur into outer space (Whereupon it explodes) and then he grabs Emperor Awesome and flings him clean through the planet they were fighting on.
"The Hero" had quite a few, with Wander and Sylvia easily getting through the hedgemaze set up for Brad Starlight, and Princess Demurra beating up Starlight when he tries to kidnap her. "Guys it's fine, I took care of it myself. Like I said, this isn't a fairy tale."
The Prisoner has Wander casually evading everything Peepers throws at him, showing off a Bugs Bunny level of craftiness and skill.
Once the self-destruct is activated on his ship, Lord Hater casually stands about while Peepers goes into a panicking frenzy, and then only after Peepers admits that Wander outwitted him does Lord Hater rather casually give the passcode to halt the self-destruct sequence. He's certainly competent and imposing when he needs to be.
Sylvia using sleeping Wander to beat up all the baddies in Hater's ship in "The Day".