I'm not a total expert, for example the only Welsh dragon I know is Idris, Ivor's chum, whose grandfather sleeps under the mountain Cader Idris. RAF planes from Valley never fly right over Cader Idris in case they waken him, with dire results. True
The dragons with which I'm most familiar are the Dragons of Pern, now bred on a large farm in Eire. They communicate directly, mind to mind, with their partner, so you no longer have any personal secrets. They are a very fierey species and need a whole lot of fuel. However, they are huge, and can be ridden. These dragons need no training, whereas the smaller and very varied Scandinavian species most definitely do, to the extent there are training manuals published and even a DVD to help you get it right. They go through quite a few sheep, but mainly eat fish., and prefer to be ridden by children.
There is an American sub species, of which I'm only familiar with one very large gorgeous sapphire blue female.
Fortunately Daenerys has the only known specimens of the Targarian Dragon, as they are bad tempered and eat humans.
The Chinese dragons are all extinct now - they were overbred and just became too contorted, just like some of the Chinese goldfish and koi. I'm unfamiliar with the Indonesian sub species Womble, but I hope for your vet bills that they are not closely related to the Chinese ones. I think they are probably very similar to the micro dragons Backinwellies has mentioned, so be prepared for them to outgrow their housing. At least they will be vegetarian so you don't need to watch your sheep, but your veg patch is going to suffer, as will your neighbours' cereal crops.
Oh how could I forget Lady Sybil's Swamp Dragons in Ankh-Morpork. They are small and have big problems with getting their flamethrowing just right, so they keep blowing themselves up. The species is beginning to mutate, with Errol, who shoots his flame backwards. Perhaps they will have more chance of success.