A compilation of guesswork about canon dragons and their councils.
The Fourth Age Dragon Councils.....
Barsaive Council
Obviously the ancient dragon Council most is known about. This dragon council never had more than a dozen members. The dragons of this council ended up fighting against the Theran empire on multiple occasions. At least 3 greats fell in battle against them. Sometime during after Earthdawn times, something must have happened to drive the dragons away from Barsaive. ( In some cases far, far away) None of the surviving great dragons of Barsaive lair in that region. Members include: ( The last three are guesses on my part )
Mountainshadow ( Dunklezahn )
IceWing ( Ghostwalker )
Usun ( Sirrurg )
Aban -- Fate unknown ( given her isolationist nature, quite possibly alive )
Earthroot -- Fate unknown ( Likely killed before the end of the fourth age, Cathay dragon )
Alamais -- Lived in Barsaive for awhile. Apparently didn't attend council meetings after the scourge. Possibly rejoined the Vasgothia dragon council.
Vasdenjas -- He's dead Jim. ( Therans )
Vestrivan -- dead.
Cloudtamer -- dead again ... Therans
Yuichotol -- another Theran casualty
Red Wing -- killed by a horror
Thermail -- killed herself
Charcoalgrin (Hestaby ) -- Personality seems a strong match. The "charcoal grin" could have gone away when Charcoalgrin became a great.
Nightsky (Celedyr) -- It would take a very specific set of events for a Eastern dragon to be a Western dragon's sire. Events that seem to match Nightsky's story. Coloration could have changed when Nightsky became a great and is close to Nightsky's anyways. Celedyr seems to have had a falling out with the other dragons involving the "Great Tree". It may explain why he went to Britain and the other dragons went to the Americas.
Masaru -- The egg given to Earthroot by Nightsky. The timing is just about right. Besides that Masaru's coloration seems to give away his parentage. (It should be noted that Masaru awas never a great in the fourth age, and unlikely part of the Barsaive council. )
Vasgothia Council
An almost never mentioned group of dragons lairing just outside of Vasgothia. All evidence suggests that this council was located in what would become Germany. ( which would explain the disproportional amount of great dragons that woke up there. ) Likely members include:
Lofwyr
Nachtmeister
Feuerschwinge
Kaltenstein
Schwartzkopf
Rhonabwy ( Rhonabwy may have a history with Lofwyr as hinted in DotSW)
Alamais ( though forced out by his brother )
Cathay Council
A council made up of Eastern dragons that had limited contact with the Barsaive Council. For a race that floated an island above the Pacific Ocean they don't seem to have many surviving members. Perhaps they were hunted down. Perhaps they just like the private life. Various members included.....
Earthroot ( Root Protector ) -- Relocated to Barsaive possibly after a fight with "White Lotus" -- likely dead
Luung ( obviously Lung )
Ryumyo
White Lotus -- fate unknown
Dvilgaynon -- fate unknown
Feathered Dragon Council(s)
Back in the fourth age a rift developed between two factions of feathered dragons. One believed that the use of "Death magic" ( a kind of blood magic ) was dangerous and only "Life Magic" (another kind of blood magic) should be used. The other faction believed in using "Death magic". Open fighting had broken out between the two factions. This fight seems to mirror the current conflict between Amazonia and Aztlan. The locations of these Council(s) are difficult to say. Most of them seem to be located around South and Central America. However South Africa seems to be location as well. Given their diverse locations and the internal strife there could have been multiple Feathered Dragon Councils or perhaps the council system simply fell apart entirely. Possible greats include.....
Hualpa
Arleesh
( Unknown dragon in Amazonia takeover )
( Possible great connected to Aztechnology )
Mujaji
Leviathan Council
Once the seas had multiple Leviathans. Now.... It is rumored that there is but one. It is known that there were multiple Leviathans after the scourge in the fourth age. However sometime before the end of the fourth age, it is suspected that some calamity fell upon the leviathan race. For when Rhonabwy mated with the sea dragon she was lamenting that she was the last. ( It must be close because the eggs are still well eggs )
Independents?
No Information can really be found on the following seemingly independent dragons. No evidence exists about what kind of councils (if any) these dragons were part of. A few thoughts......
Aden ( if Aden truly is the only Great Sirrush then responsiblity of raising the next generation of Sirrush dragons falls entirely on his shoulders. It could explain much about Aden's reclusive nature and middle-east agenda.)
Mole Skin -- fate unknown but likely dead (At least one elf (known as a watcher) in the Aztlan file seemed to claim to have omniscent powers similar to that of the grub-like dragon Mole Skin. Could elves have mated with that dragon. (Ew!) with the hope of rearing elves with that ability? )
Next to nothing is known about Australian dragons.