Used this list to climb from Gold to Mythic for the first time. Credits for the deck go to Jeff Hoogland.

Maindeck:

4x Knight of the Ebon Legion and 4x Fervent Champion: The best one-drop knights in Rakdos. Ebon Legion is of course fantastic, and Fervent Champion has nice synergy with several cards in the deck, most notably Blacklance Paragon and Stormfist Crusader.

4x Stormfist Crusader: An insane card as long as you're the aggressive deck, but can be a bit rough against decks like mono red. Draws cards, is evasive, and enables spectacle. One of the all-stars of the deck.

4x Order of Midnight: Provides some value in grindier matchups by recurring creatures while serving as a serviceable evasive threat against slower decks.

3x Smitten Swordmaster: One of the cards I was most skeptical of at first, but has proven its worth. A fairly common play pattern is turn one Ebon Legion, turn two Fervent Champion + Curry Favor to trigger Ebon Legion. Can also provide a bit of reach and an extra body to help close out games.

2x Blacklance Paragon: Works amazingly with Fervent Champion, can be a removal spell against things like Questing Beast, and is another serviceable beater against slow decks.

3x Murderous Rider: Mostly used for the removal half, but the body can be useful in a pinch, particularly against other aggressive decks.

3x Drill Bit: Excellent card against slow decks, which there are enough of to justify running this in the main. Comes out against aggressive decks and matchups where it is harder to trigger spectacle.

4x Spawn of Mayhem: Another all-star. Large evasive body that triggers spectacle, isn't legendary, pumps Ebon Legion, and does just about anything else you need. Curving Stormfist Crusader into Spawn is very hard to beat.

3x Rankle, Master of Pranks: Yet another all-star. Every mode is relevant, although I occasionally find myself not having fodder for the sac a creature mode.

2x Embercleave: Another card I was initially skeptical of. Provides good reach to close out the game, can serve as a combat trick, and occasionally just ends a game on turn 3.

2x Castle Locthwain: I don't get to the stage where I'm activating this very often, but it's useful if you don't have a Crusader or Rankle to give you cards when the game goes long.

4x Tournament Grounds: One of the reasons to play knights rather than other Rakdos cards. Serves as valuable fixing for early pressure, but can be awkward sometimes, most notably with turn 3 Spawn or Swift End.

4x Fabled Passage and 1x Bloodfell Caves: Provide fixing at the cost of entering play tapped early. It's usually not a big issue, but drawing multiple early can be brutal.

4x Blood Crypt, 6x Swamp, 3x Mountain: The manabase has been reasonable. You aren't always able to play Spawn or Swift End on turn 3, but that's the only mana issue I've had on a semi-regular basis.

Sideboard:

2x Disfigure: Useful against other aggressive decks and adventure decks.

2x Duress: Helps against most Golos and Fires decks.

2x Legion's End: Excellent card against several decks. Might deserve to be in the main in some number.

4x Noxious Grasp: Helps against big green dudes, which this deck can struggle against. Also deals with Oko and Nissa, both of which can be problematic.

3x Lava Coil: Good removal against non-green creatures and can deal with Wicked Wolf.

1x Murderous Rider: Honestly this should probably be something else. Its obviously a good card in general, but I very rarely find myself bringing it in and actually end up trimming Riders fairly often.

1x Ashiok, Dream Render: Can slow down Golos immensely and clears the yard against Esper Dance and Phoenix decks. This deck is already great against Golos and the other decks aren't particularly popular at the moment, so this spot could also be changed.