24 Creatures
Atarka, World Render: Giving all my Dragons double strike to win in one fell swoop. Yessiree.
Balefire Dragon: A trick for an unblocked Scion. A bit better than Ryusei, so we put him in, especially coupled with Scourge of the Throne.
Birds of Paradise: Enter manadorks. Birds gives one mana of any color on a dork for one mana. An easy include for any five color deck.
Bladewing the Risen: This is Unburial Rites on a Dragon that can also pump everybody for . Who would I be if I didn't take that.
Deathbringer Regent: Boardwipes can be devastating in commander. This is a boardwipe on a Dragon, and even boardwiping yourself can help. If you want a massive reanimator from Patriarch's Bidding or Living Death, this is a good way to go about it.
Dragonlord Dromoka: Are your opponents trying to counter your spells? Are they trying to bounce your creatures? Do you want them to stop. Copy Dragonlord Dromoka and reanimate her. Now your opponents can't do anything during your turn. Awesome!
Dragonmaster Outcast: This is a one-drop that should never be played on turn one. But, if you have 6 lands, making a Dragon every turn is an effect that is very hard to pass up.
Dragonspeaker Shaman: For 3 mana I can reduce the cost of all my dragons by . Sign me up!
Karrthus, Tyrant of Jund: Feel free to run Standardize and turn this into Insurrection, but I'll keep him just because he's a better haste enabler than Dragonlord Kolaghan, and you get to steal everybody else's dragons if they have any.
Keiga, the Tide Star: Who wants some shenanigans? If you use Volrath's Stronghold to recur this, and then sneak it into play, you'll take control of one permanent per turn. I love it.
Kolaghan, the Storm's Fury: This guy pumps up your dragons for each one attacking. His effect somewhat resembles that of Jazal Goldmane, but for free and without boosting toughness. I won't complain, though. He can also dodge removal with his dash cost, which is pretty cool.
Mirrorwing Dragon: This is a Dragon I don't see very often in Scion decks, but if you couple this with a Become Immense, all of your Dragons get +6/+6. That is an easy way to win, especially when coupled with Bower Passage and/or Sun Quan, Lord of Wu.
Nicol Bolas: If someone is foolish enough to let an un-transformed Scion through, or if they don't have a blocker, you can transform it into this guy and make them discard their hand. It's a cruel trick, but an effective one.
Quicksilver Dragon: This is a techy choice that can protect Scion from most targeted removal, and turn it back on your opponents. If they don't expect it, you can turn it to the biggest threat on the table.
Scalelord Reckoner: This is another tool to punish your opponents for targeted removal, or even cards that tap yours. Again, if it's unexpected, you could gravely punish an opponent.
Scourge of the Throne: Who wants an extra combat phase? ME! ME! ME! As long as you don't have the highest life, you'll get one. If you've played Rite of Replication, you'll get even more.
Scourge of Valkas: This with a Rite of Replication deals 180 damage!. 5 triggers from each of 6 dragons for 6 damage. 5 x 6 x 6 = 180. This can also do a large amount of damage if you have a massive Living Death.
Silumgar, the Drifting Death: This is a one-sided boardwipe that even gets rid of indestructible creatures. Attack with 13 dragons and destroy a Blightsteel Colossus. I'll keep it.
Sun Quan, Lord of Wu. It either feels really good to be the only person with horsemanship at a table, or the person who didn't forget horsemanship at a table where everybody else but one did. Plus he can couple with Bower Passage to make someone use horsemanship and reach to block a single dragon. Or a Dragon Hunter, but who plays him?
Steel Hellkite: A third trick for an unblocked Scion that can destroy troublesome permanents for their cmc in colorless mana. This can get rid of a great deal of threats.
Teneb, the Harvester: is a free reanimator trigger if they forget to block your dragon. That's 5 mana to reanimate a creature if it's Scion, or 3 for Teneb. With Sun Quan it's ridiculously easy.
The Ur-Dragon: I love cheating 9 mana dragons into play for cheap. Animate Dead or Unburial Rites brings him back after Scion sends him away, and then you'll have a 10 (or 9)/10 flier that reduces the cost of your dragons. Should be an auto include in Scion decks.
Utvara Hellkite: If you full swing, this Hellkite will double your board presence. That's absolutely incredible! Such a large amount of Dragons makes Become Immense + Mirrorwing Dragon
a death sentence.
Wasitora, Nekoru Queen: Sacrifices are a great way to get around Voltron commanders, or go tall strategies like Arahbo, Roar of the World. It can also make more dragons after a boardwipe.