What kind of dragon you want? This is the option of dragon i know:
1. Moonstone dragon (neutral, wise, & healer type of dragon. They have powerful radiant breath and can create a beam of energy as long as 12 feet long.)
2. Brass Dragon (Chaotic Good, but arrogance and has fire breath and sleep gas breath)
3. Ancient White Dragon (Expert Hunters, and the most powerful of the primal and predatory)
4. Shadow Dragons (the breath weapon so dangerous, have resistance to nearly every damage type when not in bright light)
5. Ancient Copper Dragon (have a unique slowing breath, Chaotic good)
6. Metallic Greatwyrms (have ice power & breath, and sensitive)
7. Ancient Radiant Dragon also known as star/celestial dragon (incredibly powerful, avenger, and has lightning magic & breath)
8. Green Dragon (cunning and manipulative by nature)
9. Ancient Dragon Turtle (Aquatic type of dragon, water magic, sensitive)
10. The Ancient Black Dragon (Sadistic, looner, very smart, persuasive, yet very powerful & dangerous)
11. Ancient Steel Dragon (live among humans, but they do so in the dark, so they can observe them without being caught, They don't see humans as prey. Instead, they are curious about them and prefer to interact with humans, elves, and dwarves instead of other dragons, since they see them as tyrants. Steel dragons breathe acid and poisonous gas)
12. Elder Brain Dragon (Psionic Beast, have horrific and unique power, and have most dangerous ability)
13. Ancient Bronze Dragons (lawful good, Arrogant but fair, have an interest in war. They live to fight against injustice and tyranny and enthusiastically lend their immense power to good causes, and have unique propulsion breath alongside lightning)
14. The Gem Greatwyrm (have telekinesis power, one of the strongest dragons)
15. Tiamat, a mythic dragon & the goddess of dragon (have very dangerous and horrific breath than can instantly killing people, and sadistic, strongest type of dragon)
16. Ancient Blue Dragon (lawful evil, hierarchical societies with themselves at the top, have unique instinc, and bossy)
17. Ancient Crystal Dragon (have crystal type of breath, will avoid battles, neutral, and very defensive if people hurt them)
18. Ancient Silver Dragon (Merciful but mighty, a good ally, lawfu good dragon, enjoy adopting a human form to socialize with others, the second most powerful metallic dragon, Its most devastating weapon is the paralyzing breath)
19. Dracoliches, the undead dragon (lawful & chaotic evil, unstoppable, eternal)
20. Ancient Red Dragon or fire dragon (lack tricks or unique abilities, they carry the day with sheer physical might and devastating fire breath, most intelligent and unpredictable)
21. Bahamut, the god of metallic dragons (a lawful good dragon, often balance the scales for good, the most powerful and well-known deities, capabilities in combat, and ideal leaders for an army)
22. Ancient Gold Dragon (a lawful good creatures who consider themselves distant and grim arbiters of justice. They usually keep to themselves until they need to right a great wrong and consider people as ally)
23. The Chromatic Greatwyrms (most dangerous dragon, can create elemental explosions, causing ruinous damage to anything that approaches them once they unlock their full potential as Mythic Monsters)
24. The Ancient Amethyst Dragon (a typically neutral dragon that has Psionic Abilities. They combine the physical prowess of other ancient dragons, complete with powerful breath attacks, alongside fearsome psionics. Furthermore, a combination of their breath weapon and Explosive Crystal legendary action can leave creatures prone and helpless to get up)