Just went ahead when reading your message to partly copy /paste something I just responded to on another post.
The first dragons, yes there are two! To start meditating with, are the blue (water) and red (fire) dragons. Why these dragons? Because Earth's and our main element is water. And water's opposing element is fire, this also symbolizes the kundalini (dragon) awakening of your spiritual being. Now it could well be that your kundalini has already awakened, which means you can start working with them as soon as you've intentionally meditated with them.
The blue and red dragons both look like the ones from Chinese folklore. As soon as you've connected with them both, your green dragon (root Chakra) will be available for you straight away. Meaning you'll have three straight off.
What may make it easier for your mediation, or anyone else for that matter is getting a crystal dragon skull, whichever one you draw to most. And for the first two dragons, a red and blue gem, small ones you can hold in your hand. (don't get red chalcedony, for the our and Earth's vibrations are to high for it to work positively on us anymore). Red and blue agate could be nice gems to start off with.
Now as follows the dragons I've come across with as of yet in chronological order:
Fifth dimensional :
Black Dragon (one you can only pass if you're ready to face your fears, very powerful energy not for those feint of heart).
Astral dragon. (6d dragon)
Sixth dimensional :
Seventh dimensional :
Eighth dimensional dragon :
Golden dragon aka. Sol known as our Sun. He is not your, nor my guide. But the Dragon patriarch of our solar system.
One special dragon, the LOVE dragon or to better understand the Life-Binding dragon. She/he is specially dedicated to two souls, whom have both acknowledged their twinflame connection.
Now their may well be a whole lot more dragons!! Some I've only recently found out about, which I could have started working with months ago. Your intent is really important. They might give you tell tales or signs, but you are the one that needs to put out the message to start your dragon's spiritual journey.
Hopefully this has helped you! =)