Earth dragon magick is a good form building long-lasting foundations, for helping to complete long-range goals, and for invoking stability into your life. You can also call on them for physical and mental endurance as well as the strength to accept responsibility. If you are planning to do a spell for enduring prosperity and success, earth dragons are excellent for this but they expect you to work towards your goals and not demand that they deliver it to you.

Other kinds of Earth Dragons are Stone Dragons, Nature Dragons, Mountain Dragons, and Forest Dragons.

Chaos Dragons
These dragons don't have a ruler, their color is pure black, and their homes are in Elemental Chaos. These dragons are always dark colors that blend into blackness, often it will look like they have stars caught in their scales. Their bodies are heavy and huge; in fact, they tend to be the largest of all dragons. They have wide, wedge-shaped heads and their long tails often are barbed or spiked. Chaos dragons have huge wings that often blend into the night sky and may be hard to make out; they are masters of camouflage in spite of their large bulk and are rarely seen if they don't wish it.

These dragons are not evil or malicious, they work with us and their magick is often incomprehensible to us and they go beyond our limited view of happenings. Because of this their acts may seem cruel, but they are working for our greater good. These dragons are pure representations of chaos and we are to call on them when we realize that not every problem or situation can be resolved with order and reasoning. When working with these dragons they will go straight to the source of your problem or question and force you to confront it. This can be rather uncomfortable for us as we will need to deal with hidden aspects of ourselves that we may not be ready to face, so be sure that you are prepared to accept the consequences of invoking a chaos dragon. Chaos Dragons do not act as Guardians nor Guides.

Chaos dragon magic is mainly concerned with the re-creation of lives, relationships, and careers. You can employ them to help break through barriers, with changing luck, and in bringing about vast changes. 
You can work with them to explore past lives and their magick is particularly powerful aids in divination. 

Their magick is also used to confine anything that will hinder you in forwarding growth and movement if you invoke this aspect of them be prepared to have everything that is holding you back leave your life whether you want it gone or not. This is the type of dragon that we work with when we talk about 'riding the dragon’; eventually, during this ritual, we will have to confront our worst enemy ~ ourselves... Chaos Dragons can also be heralds warning of catastrophe, to ignore what they have to say may bring about destruction in our lives. 

Dragon Deities:
Dragon God Gneicht;
Gneicht is the ruler of the Night... of doorways (both opening and closing them) 
As a guide his visit speaks of opportunities, both taken and missed, depending on the type of message he brings you...

Morthan (moor'-z'dan) 
Dragon Goddess of bountiful harvests of all kinds; Mother aspect of Dragon kind. Nurturing, Protective, and Generous...
Call on Morthan when in need of emotional support or financial assistance.

Veaug (vog) 
Dragon God of obscurity and that which is hidden; does not like assisting in hiding actions or objects. This dragon is adept at finding things from the Ancients that have been lost in obscurity (old tomes, amulets, magickal items) His assistance can further the summoners knowledge greatly, but he is easily angered, be sure that the item you seek is worth his time before calling upon him...

Luqueas (luk-wee-ass, long U, long E) 
Dragon trickster God; take great care when inviting His presence. He is a joker, a wild card. His action is not always in the best interest of the summoner. He is like a politician, he can talk circles around most people & beings, but his words are not always truthful. He can be a strong ally... If you are careful. 

Tysteal (tiss'-dell) 
Dragon shepherd Goddess; guardian of the meek; a dragon person's first line of defense.
Call upon Tysteal when in need of Protection.

Mordak (moo-ór-dak) 
Dragon God of war, vengeance, and retributions of all kinds; make dead certain that you are within your magickal rights before calling Him down, as he is not amused by a fallacious summons.

Davliteau (dav-lí-too) 
Dragon God of conjured entities; very helpful in ridding one's self of "sent" conjurations and the like; benevolent to the core; very helpful and willing attendant being, though He has little power in other areas. He acts as a protector from other Beings or Dragons who are sent to harass or harm you. He can be called upon when you are having trouble controlling one of the lesser Beings. 

Ouida (o-weed'-a, long O, soft a) 
 Dragon Goddess of guidance. 
Call upon Ouida when you are uncertain of your Path if you are unsure of which life-choice to make. She can help with decisions about finances, marriage, carrier choices, etc.  
She is one who stands in the Doorway of Time, Looking both ways at once. 

Solange (so-londg') 
Dragon deity of healing. Though Dragons rarely become involved in human affairs, Solange cares about those who care for others. He will lend a healing touch to any beneficial healing spell, but there is a price for His assistance. He requires the planting of fruit trees (three at the least and 9 at the most) for his services. He will also attend to your herb garden and bless it with His dragon power.

Ryusan (rí-u-san, long I, long U) 
Translates literally to "my dragon."  Ryusan, of the three-headed Japanese variety, is best at consoling and nurturing a hurt spirit, whether it be in a host body or not. Ryusan is an expert at guiding spirits on to their next journey. Ryusan can contact those who have passed on. He is a Guardian of the Veil and stands between our realm and the realm beyond. This is the Dragon you would call upon with assistance in Divination.

List of Sources: 
D. J. Conway's book 'Dancing with Dragons' 
http://www.amazon.com/s/ref=nb_sb_ss_i_2_13?url=search-alias%3Daps&...

Lady of the Earth  
http://www.ladyoftheearth.com/dragon/dragon.html

Clan of the Dragon
http://ebon-dragon.com/cotd/Honor.html

Ted Andrews's book 'Enchantment of the Faerie Realm'
http://www.amazon.com/Enchantment-Faerie-Realm-Communicate-Elementa...