Ever since Dominaria hit Standard, players have been looking for the best Karn, Scion of Urza deck. There's a lot of questions to be answered about which abilities you should be trying to prioritize. Are the card advantage abilities good enough on their own? Or should you be trying to leverage the artifact synergies and treat Karn as a Gideon, Ally of Zendikar? Early indications are that both methods are correct, but that it's harder to find a shell that lets you go all-in on Artifacts. That said, it looks like Raphaell has found a way to do it and in style:

Construct Tribal - Dominaria Standard | WOTC_Writer_Raphaell, 5-0 Standard League

• Creatures (30)
• 3 Scrap Trawler
• 3 Scrapheap Scrounger
• 4 Bomat Courier
• 4 Chief of the Foundry
• 4 Foundry Inspector
• 4 Merchant's Dockhand
• 4 Metallic Mimic
• 4 Walking Ballista

• Planeswalkers (4)
• 4 Karn, Scion of Urza

• Enchantments (3)
• 3 The Antiquities War

• Lands (23)
• 5 Island
• 2 Inventors' Fair
• 4 Aether Hub
• 4 Spire of Industry
• 4 Spirebluff Canal
• 4 Zhalfirin Void

• Sideboard (15)
• 2 Aethersphere Harvester
• 4 Blink of an Eye
• 4 Metallic Rebuke
• 1 Negate
• 1 Scrap Trawler
• 2 Sorcerous Spyglass
• 1 The Antiquities War

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Bomat Courier gives you early pressure and late-game card advantage. Foundry Inspector and Chief of the Foundry are additional lord-esque effects that let you do unfair things. Scrapheap Scrounger and Scrap Trawler give you card advantage in late games. On top of all that, Karn is going to be making 4/4 tokens on the regular and you get to use The Antiquities War as card advantage plus an Overrun.

And this is without really committing to any colors. There are other variations of this deck that lean on Verdurous Gearhulk and Winding Constrictor as well as Adventurous Impulse to smooth your mana and give you more consistent access to the more powerful creatures in your deck.

The important lesson here is that Karn isn't just for midrange and control decks. He is a powerful curve-topper for aggressive decks that leverage artifact synergies. If it wasn't clear at first that there were enough cheap, aggressive artifact creatures to support this type of strategy, it certainly is now.