The driving logic behind building Lathliss over any of the multitude of other options to head up a dragon deck was maximum dragon for minimum effort. I'd just built Golos so wasn't interested in any of the five colour options, and getting a free token for every dragon incentivises playing a lot of dragons, as opposed to just a few that you combo with a la Scion of the Ur-Dragon. I tend to do the first draft of a deck with the 8x8 method just to organise my thoughts, and this deck had six columns headed up with 'Dragons'. Also monocolour is the easiest manabase construction in existence, which is a blessing after a 5c deck.
The deck snowballs very easily, has a tendency to suffer for a few turns when a wrath happens, and in terms of power level is clearly not tearing up a cEDH table but will happily tangle with a precon without too many issues. For wrath resilience without going too far afield in terms of colours and general strategy, I recommend Bladewing the Risen. Gets you reanimation from the command zone as well as general graveyard play, including tribal all-star Patriarch's Bidding.
In terms of psychographics, this deck is almost pure Timmy, in the classic sense of 'play big things while cackling gleefully'. If swamping the board with giant firebreathing lizards is your idea of a fun time then this is the deck for you. It's also a great entry point into the format in terms of ease of play and budgetary concerns, so even if it's not your general thing then having a copy sleeved up to loan out to potential new players might not be the worst idea.
This deck is pretty cheap, and I suspect even with all the vagaries of the singles market will always be cheap outside of a few cards. The expensive stuff is mostly ramp like Extraplanar Lens and Nykthos, Shrine to Nyx, which while nice are not essential. If you're looking to stay in mono-red, I'd replace them with some of the recent enchantments such as Fires of Invention and Sunbird's Invocation, which once you've got going will allow you to keep going without too much input mana wise.
However, if you want to go dragon tribal but you've got all the budget in the world? Scion of the Ur-Dragon if you're feeling more combo-y, The Ur-Dragon if you just want to slam your favourite thirty or so dragons into a deck and back them up with ramp and card draw. For intermediate budgets, there's a few good two or three colour options including Atarka, World Render, Bladewing the Risen, Kolaghan, the Storm's Fury and the classic of Karrthus, Tyrant of Jund.
I would also say the quicker your start, the more you have to think about sandbagging a couple of dragons, cause you *will* scare the table and draw a fair bit of focus. It's fairly easy for this deck to have roughly 20 flying power turn four or five, and in my meta at least that's generally when everyone else is starting to move out of the early game so isn't quite at haymaker stage yet.
The only real disruption that can cause you issues here is being wrathed. Even if someone kills Lathliss, you still have a board full of flyers. Possibility Storm is a fantastic way to cause your opponents a headache here, because your entire deck is approximately the same things, so you know that you're gonna pay 6 mana, get a beefy flyer, and unless there's a very specific effect you're after you don't really care which beefy flyer it is. As mentioned earlier, I do recommend taking advantage of the fact you're churning out free 5/5's and saving a couple of dragons for if you do have to rebuild after a wrath.
Scourge of Valkas/Dragon Tempest: If you can get one of these to stick, every dragon is just chunks of damage. Also triggers off the tokens Lathliss makes, so make sure you keep track of what order the triggers are in.
Sarkhan, Dragonsoul: I got to ult this guy once, somehow. Pulled out roughly half the dragons in the deck plus the previously mentioned Scourge of Valkas and dealt some unnecessarily large amount of damage to the table. Absolutely amazing, but a bit telegraphed if anyone is paying attention.
Lukka, Coppercoat Outcast: The ult here is pretty tasty as well, and if you've drawn him late not that hard to get to. I'd initially read it as 'target opponent' and kind of dismissed it, but each opponent? You can easily get 30-40 power on the board late game and just nuke everyone.
Additional stuff to help with the combat finisher includes:
Utvara Hellkite: Yes, it's a bit win more sometimes. Sometimes though, Lathliss is costing you like, 12 mana and you've got a few things in play. You drop this, swing with what you've got and at worst you have same amount of stuff you did before swinging.
Moonveil Dragon: Backup Lathliss basically. Also cheaper to activate, which is really handy. I sometimes find with the I'll be like, one activation off killing the table.
Ok so first off, any Dragon not previously mentioned? Probably not vital to the deck beyond the creature type. They all do *something* other than being a vanilla flyer, but generally not something essential. That does give a lot of wiggle room for your own build though, because there's a bunch of cool stuff that sits on that 'french vanilla beater' line that I didn't include, so if you really like Tarox Bladewing because it's got that sweet frame? Sling him in! That said, there are a few that I'm unlikely to cut, and would recommend making sure you include:
Steel Hellkite: Gets around pro-red, gives you some broad spectrum removal.
Hoard-Smelter Dragon: Kills Akroma's Memorial. I mean, it'll deal with a lot of other stuff too, but this deck loses to the Memorial so quickly it's unreal.
Opportunistic Dragon: Slows down opponents by nicking a mana rock, occasionally turns off a general, comes down early if you're not seeing any ramp.
Dragon tribal stuff:
Thunderbreak Regent: There's a Hanna, Ship's Navigator prison deck running all the Arrest variants you can think of in my meta, which this helps to deal with. Acts as a bit of a lightning rod for spot removal, also makes people think twice before going all in on individually tapping your stuff down if they're just gonna take half the damage anyway.
Utvara Hellkite: Who doesn't like swinging with a bunch of dragons and getting more? Massively improved with Dragon Tempest or similar in play, because often you'll just kill half a table.
Dragon's Hoard: This will draw you so many cards. It's not unusual to end up with 20 counters on it, and nobody ever wants to spend removal to get rid of it.
Dragonlord's Servant/Dragonspeaker Shaman: I favour these effects over rocks because they apply to each and every play as long as generic mana is involved somewhere. Having both of these out essentially makes all your dragons half price, which mean you can get to critical mass incredibly fast.
Crucible of Fire: What's better than free 5/5 every turn? A free 8/8 every turn! Makes Lathliss a 3 turn clock by herself with zero input, and if we assume the platonic stats for a dragon is 5/5, essentially adds half a dragon to every single one you play.
Kindred Charge: If casting this doesn't kill a minimum of one player either through triggers or just raw combat damage, something's gone very wrong for you. Absolutely fantastic finisher.
Vanquisher's Banner: The anthem is a bit irrelevant, but you can often just chain dragons together, especially once the cost reducers/mana doublers are in play. Also we're mono-red, so any card draw is a good thing and it doesn't need us to do anything we wouldn't have been doing anyway. Also has a cute synergy with Path of Ancestry, cause if you use the Path you can hopefully scry away something irrelevant and draw into more dragons.
Sarkhan's Triumph: Gets you what you need, when you need it. Also is an instant, so you can use it to set up your Scourge of Valkas turn, but will also toolbox if there's a particular problem you need to deal with. Scourge of Kher Ridges for tokens, Hoard-Smelter Dragon for artifacts, Knollspine Dragon if you're running low on cards and there's a juicy target.
Crucible of the Spirit Dragon: It's not much, but you probably have the odd turn here or there to stock this up. Handy for those starts where you don't see any of your other ramp, in a pinch it gets you a turn 4 or 5 Lathliss so that then you can start curving from her a turn or so early. There's also a non-zero amount of activated abilities, and sometimes that extra few mana into Lathliss will swing the game.
Haven of the Spirit Dragon: Sometimes Scourge of Valkas dies, or Lathliss just gets uncastable from the CZ, so this is in here as backup for those situations.
Path of Ancestry: This is pretty much scry 1 every turn, which is invaluable as there's not a lot of card advantage in here so having something that smooths out draws for zero investment is great.
Sarkhan Fireblood: Turn 3 this guy, turn 4 Lathliss is pretty solid. Also helps dig through land clumps. I don't think I've ever used the ult, but it's handy recovery from a wrath if nothing else.
Sarkhan, Dragonsoul: He's in here purely for the ult, although clearing out X/1 utility creatures while you get there is reasonable too. That ult though. As mentioned, I only managed it once so far, but it will end the game on the spot.
Sarkhan the Masterless: At some point, people are going to start thinking 'that guy has a lot of dragons, but I can probably out-attack him if I strike now'. Not with Sarkhan the Masterless in play they can't. At worst, they'll just lose all their creatures, at best it's mutually assured destruction time. Honestly, this could be an enchantment, but sometimes you get a few extra dragons to swing with with the + ability.
Relevant non-Dragon stuff I haven't already mentioned:
Magmaquake: There was a superfriends deck in my meta when I built this so this got thrown in to help curb that, and now sticks around as another hedge against weenies/tokens alongside Scourge of Kher Ridges.
Panharmonicon: This does so much. The floor is an additional token from Lathliss, but the ceiling is double Scourge of Valkas triggers. Absolute nonsense will happen if this sticks around for any length of time.
I'm not running changelings because I didn't think I needed them, and I generally dislike using them in a tribal deck, especially one that has options from nearly every set in the games history. There's also the fact that a lot of them don't have flying, and knowing all your attackers have built in evasion makes life a lot easier when you're swinging with the absolute mess of stuff you can end up with on the board. I'm all about reducing the mental load for both myself and my opponents.
Dragonstorm was in the deck to start with, but you're generally just not going get the storm count to anywhere relevant, so I cut it. Shared Animosity was in the deck to start with as well, but was largely underwhelming. There's various other tribal support stuff and/or new dragons that haven't made it in through a combination of me either not knowing it existed when I built the deck or CV19 meaning it's too new for me to have paid attention to. Of that, Terror of the Peaks, Leyline Tyrant and Cryptic Gateway will likely end up in the deck once I'm seeing the table more often.
I'm not running Sneak Attack or similar effects because I don't want to sacrifice my dragons, I want them to stick around and swing every turn. Nothing wrong with them though, they're undoubtedly powerful and you keep the token if Lathliss is out.
Out: Dragonstorm, Brass Herald, Stormwing Dragon
In: Solemn Simulacrum, Lightning Greaves, Darksteel Ingot
03/05/19
Out: Coat of Arms
In: Sarkhan the Masterless
10/09/19
Out: Shared Animosity
In: Panharmonicon
13/09/19
Out: Imperial Hellkite
In: Drakuseth, Maw of Flames
29/09/19
Out: Siege Dragon
In: Opportunistic Dragon
20/06/21
Out: Demanding Dragon
In: Obsidian Charmaw
05/06/22
Out: Bogardan Hellkite, Furyborn Hellkite
In: Ganax, Astral Hunter, Wrathful Red Dragon
15/11/22
Out: Akoum Hellkite, Ancient Hellkite, Drakuseth, Maw of Flames, Dream Pillager, Kilnmouth Dragon, Knollspine Dragon, Scourge of Kher Ridges, Skyline Despot, Spawn of Thraxes, Tyrant of Valakut
In: Armillary Sphere, Atsushi, the Blazing Sky, Carnelian Orb of Dragonkind, Cryptic Gateway, Icon of Ancestry, Leyline Tyrant, Phyrexian Dragon Engine, Spit Flame, Sunbird's Invocation, Terror of the Peaks
05/02/23
Out: Mana-Charged Dragon
In: Ancient Copper Dragon
18/02/23
Out: Cryptic Gateway, Sarkhan's Unsealing
In: Koth, Fire of Resistance, Orb of Dragonkind