The only major dragons we know are Midgardsormr and Hraesvelgr. Hraesvelgr openly wants nothing to do with the mortal races anymore; he only aided us against Nidhogg because Midgardsormr directly asked him to, and then he returned to Zenith and his isolation (he reappears at the end of Alphascape, but again, Middy asked him for the favor, and again, he takes off afterwards). Midgardsormr used up the last of his power to save the WoL from Omega at the end of the Sigmascape, and one of the Tales From the Shadows indicates that, while he's watching the world, he won't wake up again for a century or more.