I would run more cards that give bonuses when they attack as the effects would stack with the extra phases. (attack once, +1/+0, attack again for additional +1/+0 (+2/+0 in total) with battle cry). Any creature with Battle cry works and a quick gatherer search will get more.

One of the best Aurelia, the Warleader decks I have seen so far, question though, why not add Gratuitous Violence? I understand like Dictate of the Twin Gods since your using Aurelia, the Warleader as your commander opponents doing double damage would hurt like hell, but Gratuitous Violence is only YOUR damage :D So you could LITERALLY win in one turn with Aurelia, the Warleader with enough counters or whatever on her :D I play a Gisela, Blade of Goldnight deck, and I definitely want to make an Aurelia, the Warleader sort of based off your deck since I love eeeeeeeeeet Boros <3

Suggested Swaps:

Boros Reckoner -> Luminarch Ascension

Reckoner feels weak in this list unless you strictly play 1v1 (in which case, ignore this suggestion since Luminarch is only good in multiplayer). Luminarch turns on after 1 round around the board in a standard 4-player free for all, and then here comes the angel hurt.

Moonhold -> Silence/Aurelia's Fury

Moonhold lets you screw a guy out of his land drop it's true, but Silence will give you an entire turn without people interrupting your million-and-one combat phases. Aurelia's Fury (which I know you have in your sideboard) does much the same, only it also clears the way of blockers.

Firemane Avenger -> Thundermaw Hellkite

Firemane Avenger feels fairly underwhelming in most scenarios. Thundermaw on the other hand clears the skies so Aurelia can bring the hurt. Plus, since Thundermaw has haste himself, he can join the fun.

Boros Guildgate -> Wind-Scarred Crag

Same price and Wind is strictly better.

@zen_fishy Hey, thanks for the suggestions! This is usually a 1v1 deck but I have been looking to convert it into more of a multiplayer style deck. It can work but only if I'm not targeted at all.

This deck list is actually pretty out of date. I haven't had the chance to fully update it. It still doesn't include what you've suggesested but I like they way they look and I will keep them in the maybeboard for further research. :)

Cool beans. Happy to help.

Good luck with the deck, looks fun to play. Easy +1 from me.

Have you considered Jor Kadeen, the Prevailer (with Great Furnace and Ancient Den)?

@Karns_Pyromancer Yes I have, however at 5 cmc, there's usually other creatures, spells, equipments, or costs to pay that will take precedence. Once Aurelia hits the field, it's usually game over anyway.

Have you considered Assemble the Legion? It's one of my favourite R/W cards

@AlexoBn In the same reason above, Assemble the legion is a 5 CMC enchantment that takes time to come online. There are plenty of faster more immediately impactful options to choose from; and in a 4+ player game it hardly lasts a round let alone two.

Why is Coalition Relic in there? I get that it has the potential to add 2 mana to your mana pool, but only to cast instants or activate abilities during your combat phase. And, with only 8 instants, that's some pretty limited criteria.

@TheCouchman It says precombat main phase meaning the main phase before the combat step.

OP deck! If you put in Ashlesa who smiles at death (Fate Reforged), It will be even more OP.

Also but in curse of the bloodletting (Innasrid) and Warstrom Surge (???) for even more damage.

BornofBlood Alesha can't be in this deck because of her black color identity.The others are nice though!

Boros decks are always fun to play against with how quick things can change against them. I feel the key is to stop cards like Avacyn, Angel of Hope from entering the battlefield, otherwise things get ugly quick. Have you thought of Angel of Jubilation?

any deck based around Aurelia should be running Cloudshift as well, why just swing twice when you can swing 3 times in one turn for only 1 mana?

@doozerISF Probably because it unequips her. :P

this is very true but that one extra phase can be the difference between killing one person and killing 2 in a single turn if you have just one other creature like hero of bladehold out there. not to mention the part where it lets you juke nasty little single target counters and still pull off the 3 phase nonsense since she doesn't actually have to hit to proc the trigger.

mirran crusader would also fit in nicely here, he plays very well with all the equipment and having built in protection for 3 cmc on a double striker is just plain silly.

What about Kazuul, Tyrant of the Cliffs ?

A card that is a staple for R/W is Assemble the Legion. Surprised not to see it here.

Also, Vandalblast might be a good option against most decks. Artifact mana rocks are a thing. And getting rid of someone else's Greaves or Boots is decent. Or just no one besides you can have artifacts is very nice.

Assemble the legion was already mentioned above. I'd definitely add the new chandra when she's released with oath of the gatewatch. Pretty good edh card for card draw lacking Boros decks