instead of Nature's Lore i would give Lithoform Engine while yes you have a lot of legendary's you also have a lot of good activated abilities that you can copy like the Ur dragons dragons attacking ability for double draw and 2 permanents

Lithoform Engine a try*

What's your opinion on Exploration in the deck? I know it's not an amazing late-game draw, but from experience, the deck being confined to one land drop a turn, especially with minimal ramp, tends to result in a few games where I get taken out due to not being quick enough out of the gate.

Jator Sure Lithoform Engine is good in that scenario. And there's a handful of effects that have a big impact on the game (Dragonlord Silumgar, O-Kagachi, Scaledlord) that would be worth copying. However, getting this artifact into play, having the ability to activate it with a relevant ability while casting a creature with that ability that's worth copying or Ur-Dragon even enters the "Magical Christmas Land scenario". Opponents are going to want to remove everything as soon as possible so having everything on the field and line up like that with no tutoring seems really unlikely and not worth a slot if we can't take advantage of all the modes enough.

NebulaMink Yeah Exploration seems fine. Doesn't feel as good after Turn 1 or if you aren't able to draw cards to hit multiple land drops later in the game. So if you have it, feel free to throw it in although it isn't required. If you're having issues on not being able to come out hot, cut some more top end cards for more ramp/cheating cards for your build.

I would consider more card draw and ramp. Especially cheap ramp, like sol ring, signets, and talismans. It looks like most games your first 2 turns will be play a land and pass.

jasinatael Deck has a good enough amount of ramp (could use a touch more card draw) to allow including all these cool dragons. Otherwise would have to start cutting down on creatures to add stuff like that. With a deck that's mana hungry like this, I'm personally not a big fan of non land ramp cards unless they do more than just ramp by one mana. Because inevitably, when they get destroyed by a wipe, you're left with such a mana disadvantage if you rely heavily on them. All of the artifact/creature ramp in the deck offer some sort of utility in allowing more card draw and more mana than signets ever could justifying having them specifically. I took Sol Ring out a while ago which I'm still kinda okay with because of some of the funky mana requirements for some cards in this deck but might make it's way back in. Plus, my mana curve has more 5 drop spells as opposed to 4 drop ones so loading up on signets/2 mana ramp won't be as good as the 3 drop ramp and I'll end up wasting mana and having less impactful cards.

As for the first two turns of the game, I'm personally okay with taking the first two turns off if I don't draw one of the two drops to be able to efficiently setup mana. Given the mana base, it can be extremely painful of having to fetch/shock every turn when curving out to have perfect mana. Using the first two turns to minimize losing 5-8 damage that I do to myself and guarantee the ability to have the mana requirements for anything the rest of the game is perfectly fine by me.

What's your opinion on Bloom Tender in lieu of Faeburrow Elder, and running Fist of Suns in the deck?

NebulaMink Only upside is that you can play it on Turn two. Faeburrow is a more budget friendly, can function as an attacker/blocker becoming as big as a 5/5 if you don't need the mana on a particular turn and goes more on curve with casting 5 drops immediately after as it counts for two colors. If you have one, it's good enough to try out but you know not required for the deck I would say :)

NebulaMink Only upside is that you can play it on Turn two. Faeburrow is a more budget friendly, can function as an attacker/blocker becoming as big as a 5/5 if you don't need the mana on a particular turn and goes more on curve with casting 5 drops immediately after as it counts for two colors. If you have one, it's good enough to try out but you know not required for the deck I would say :)

how do you feel about Defense of the Heart in order to tutor any 2 creatures and its not hard to trigger

I really like the deck and the theme you have going.

Just wanted to know why you don't use the original dual lands in a 5c deck?

Great deck anyways! +1

Love your deck! I´m in the process of making my own dragon Kingdown, and the Ur-Dragon is the King!

I have a few cards that i´m not sure about:

-Lurking Predators. This card is very good in all creature commander decks. Helps you to cheat your dragons and it´s great in big tables.

-Dragonspeaker Shaman. I dont know why every dragon player hates this card. I think it´s very usefull.

-Sunbird's Invocation. Expensive but worth it.

-Descendants' Path. This is a must in every tribal deck. Its cheap and makes your game quicker.

-O-Kagachi, Vengeful Kami. I like the art of this card very much, but unless you have morophon in the battlefield, i dont love it.

-Dragonmaster Outcast. Cheap and usefull, usually play it to attract the attention of removals.

-Taigam, Ojutai Master. Cavern of souls for all your dragons.

-bident of thassa. Card draw and sometimes little creatures removal. I use this againts winni/annoying commanders like Najeela, Meren and Tatyova to slow them.

-Fiery Emancipation. Usually a win-con.

-Chromatic Orrery. Multicolor-mana.

Jator Seems good! I've always thought about throwing it in because it's easy to trigger. Guess the main thing to figure out is what do you want to prioritize looking for to either gain some more card advantage or alpha strike someone. I'll definitely see if I can squeeze it into the list!

Granum Original duals are obviously the best pick. However, I don't own any OG Duals nor do I like proxying stuff like that. If you own OG Duals, go for it but not required.

EmperorPenguin I'll go fast. Lurking Predators 32 creatures in the deck, which is low for this effect, and you're forced to cast them otherwise why would you playing this card. Opens yourself up to field wipes and getting rid of a lot of your threats in the deck. Dragonspeaker Shaman Non land ramp based card that's on a small body that easy to remove that's really only good on Turn 3. Sunbird's Invocation Win more enchantment that does nothing casting it on Turn 7, which isn't guaranteed to make it back to you when you play it, where you can cast potentially two dragons instead. Descendants' Path Same thing as Predators. Low hit rate that does nothing when you play it. Granted it's only 3 mana but list is already tight so the hit rate just doesn't make it worth it. O-Kagachi, Vengeful Kami Great political card in that it deters people from swinging out of fear of blowing up their permanents. Flying and trample also really great. Dragonmaster Outcast Rather would just pay mana for a Dragon that has equivalent stats for the 5/5 that comes in rather than risk this on a small body and can actually be aggressive. Taigam, Ojutai Master Counter spells ain't a big deal and paying 4 mana to have only a Cavern of Souls that pretty much has no other lines of text that are really relevant most of the time ain't worth it. Bident of Thassa Relies on having creatures to get the card draw and the ability to make opponents attack will just make them attack you. If they have a large amount of creatures, sure you pick off importants ones, but you end up taking a lot of damage. Fiery Emancipation Win more card that relies on having creatures. With a small amount of dragons, you can usually halve someones health so relying on one effect in the deck to do more damage isn't worth. Chromatic Orrery Big 7 mana artifact that sometimes you might not be able to cast and can't easily be protected. Lot of scenarios of you getting blown out.

Why no Mana Crypt, Vault or Ancient Tomb?

heavyuser Two of those a little high on the budget and don't make a huge difference in my eyes and my mana base is already painful enough to where Tomb Damage is going to really put my lower than I want to be. Crypt could be argued for replacement of a land but with the color requirements this deck needs ramping that hard isn't going to make it better by a large amount. The deck doesn't have any problems with ramping. It's keeping up and rebuilding after your opponents interact.

I presume the new Hellkite that gives a free attack with Ur-Dragon is an auto-include?

Hellkite Courser is the bees kness.