Here's the Vault of Pandius' list of Mystara products.
http://pandius.com/prodlist.html
A little past half-way down is the list of Known World/Mystara related Dragon articles.
For new monsters, I'm not completely certain of the issue, but guessing from the VoP descriptions...
Night Dragons were introduced around #153 or #154
N'djatwa (elf/ogre cross breeds?!?!) around #158
The rakastas' flying saber-tooth tigers at around #160
Vulcanian Sloths around #161
Sky Wyrms at about #167
There were also the Winged Elves and Winged Minotaurs around #192
A lot of those articles didn't introduce new monsters, but expanded upon them - particularly the rakastas, lupins, araneas, scorpion-men, tortles, and so on. Most of those were introduced in the X-series of modules.
R.A.