In A Touch of Fever, Artie takes out an airborne artifact using the Red Baron's plane. Not only had Artie given the plane bullets made out of a steel-neutralizer alloy, but he had upgraded it with some of Goddard's rocket tech so that it could break the sound barrier.
In Regret, when Pete overcomes the power of the newest Artifact inside a prison thanks in part to (ironically) one of the inmates.
"The cruelest prison of all, is the one we build ourselves. From our own regret."
Pete and Myka using the "Wings of Icarus" to escape Warehouse 2 in Reset.
When Myka figured out how to use the Reflex-Hammer in Vendetta. It was a small, but still awesome moment.
In Don't Hate the Player, when Claudia gets strapped to a hospital bed, at first shrieking in abject terror as the really creepy doctor is about to apply a giant set of electrodes to her head. With a little help from the others, she quickly turns the situation into her moment of awesome for the episode when she shocks him instead.
Crosses over a bit with High Octane Nightmare Fuel and Crowning Moment of Heartwarming, but Claudia taking out Marcus. It makes you want to simultaneously hug her, piss your pants, and shout for joy. It was freaky.
Claudia: That was for Steve.
And then Steve returns the favour when he forces Alice Liddel out of Claudia's body. How? By using his Tesla on the mirror shard Alice was using to body hop.
Perhaps a more off-focus example, but that woman in "No Pain, No Gain" whose courage created an artifact when she stepped between a baby and a bullet.
Crosses over into Heartwarming when Mrs. F notes to Claudia that the artifact is hers (the woman's). The Warehouse only takes artifacts if someone misuses it or the artifact itself causes trouble. In other words, your good deeds in life can create something extraordinary and, in cases like this, the people that create artifacts are also the people most likely to use them (unknowingly so) for great things. And that's a pretty uplifting message.
Definitely a Crowning Moment of Heartwarming. In a series that has repeatedly shown the dangers of artifacts and that, even when trying to do good people will suffer, we finally see that there is good in the world and that the artifacts truly can be used to help and protect people.
Claudia: I hate this. The Warehouse was supposed to do good and instead it just keeps killing the people I love.
Jinx: Well, that's kind of a simplification.
Claudia: Is it though? You died. Leena died. And now the whole damn world is dying.
Jinx: Claud, Claud, Claud. Pete and Myka will find a cure. They will.
Claudia: So what? It's not going to save Leena And Artie? I stabbed Artie with a dagger. Why bother if we just keep losing?
Jinx: Because it's not the win, it's the fight. Evil is relentless. It always has been. You take one evil out and another pops up to replace it.
Claudia: Worst. Pep. Talk. Ever.
Jinx: But if we stop fighting, if we give up what does that say about us? I knew that Sykes was dangerous but we had to stop him. Ms. Frederick warned Leena to get out but she stayed to help Artie. And you? You knew the world needed saving even if it cost you the only father you've ever known. The fight. That's what matters.
Artie getting Cherie Currie to play at Claudia's 21st birthday party in "Runaways". He apparently saved her life back in the 70s.
The final scene of The Truth Hurts: Claudia staying at the Warehouse to confront Paracelsus. The stare down between the two is one of the most awesome things to happen on the show.
Artie drag-racing in "The Big Snag", completely with a 70s-style sax riff.
In "Changku Shisi", as the rest of the team travels to China to stop Alt!Valda from moving the Warehouse, Artie and Steve do what they can on their end by trying to stop one of the artifacts enabling it (a sundial). When all artifact-powered attempts to stop the sundial from moving fail, they desperately resort to looping a rope around it and desperately pulling it to try and make it stop.
Artie: Valda, you son of a bitch! This is my home, and you are never taking it away from me, do you hear me?! Never!
Pete proving he's smarter than he looks, by finding a way to solve two of the team's problems at once: he has Claudia Reverse the Polarity of Valda's mind control artifact in order to transfer Claire's uncontrollable powers to him. Then he manages to snag the artifact that enabled Valda to cross over from his timeline, Retgoning him and Claire's powers with him.