Dragonne: Hey, a new monster! These guys are a cross between a brass dragon and a lion. Their origins aren’t explained here, but I suppose a wizard did it. It’s a shame the dragon involved here isn’t the Bronze variety, because we’ve already established that they transform into other animals for a lark. Perhaps brass dragons do the same sometimes, and mate with lions while doing so? It’s noted that Dragonnes can speak the languages of Brass Dragons and Sphinxes, so perhaps the crossbreed is with those two species, and not lions after all? I think that’s a much more interesting possibility
These guys are pretty tough critters (9 hit dice) and their major attack is a roar which can weaken or deafen itheir prey. They have an Armor Class listed as 6/2, which goes unexplained in the text. Perhaps they have an AC of 6 for their lion parts, and 2 for their dragon parts?
Finally, I find the pronunciation for these guys problematic at the table. I’ve always said it like Dragon, with a greater emphasis on the second syllable. Dra-GON instead of DRA-gon. It sounds a little silly to be honest, and could cause confusion at the table. But I've never actually used one, so it hasn't come up.
Dragon Turtle: Yay! I love Dragon Turtles. They first appeared in OD&D Vol. 3, in the section for underwater encounters. I don’t think they’ve appeared since then, but I could be wrong. Their Armor Class has now improved from 2 to 0. Their Hit Dice range has increased from 11-13 to 12-14. They still have the same cloud of steam breath weapon, but now it’s dimension are more like a cloud than the red dragon’s cone. Previously they could always capsize ships, but now they have a percentile chance based on the ship’s size. Other than that they are the same, and we also get some info on their colouration and learn that they have their own language.
Dryad: Dryads first appeared in OD&D, as beautiful tree sprites with a penchant for enchanting charismatic men. A few significant things have changed about them, beginning with a drop in their Armor Class from 5 to 9, which is very steep. They are still confined to the area around their specific tree, but that area has increased from 24” to 36” (remember that the “ symbol in D&D does not refer to inches, but tens of feet). They now get the ability to use dimension door to return to their tree, which they didn’t have before. Their 50% magic resistance is also new. They still have the same charm ability, but now will generally only use it on men with a high Charisma (16+), and there’s a chance that said victim could return after 1-4 years instead of being gone forever.
Perhaps the older Dryads were a different variety, with a more bark-like appearance to account for their higher AC? The new variety aren’t yet so attuned to their trees, and so they can move farther away and use other trees to travel.
Dwarf: Dwarves first appeared in OD&D, both as a monster and player character race. They haven’t changed much at all here. It’s interesting to note that they can become psionic – that was not possible under the psionics rules in Supplement III. They get a greater range of high level characters when encountered in large numbers, and their choice of weapons and armour is described in greater detail (it’s mostly axes and hammers, but there’s a surprisingly large percentage that wield swords). They now get a +1 to attacks against goblins, orcs and hobgoblins, which I believe is new. They still get a defensive bonus against Giants and Ogres and the like, but whereas before it was expressed as them taking half damage from blows, now their attackers suffer a -4 penalty to hit. Otherwise, things are much the same as they were in OD&D. (Note, though, that a lot of things have changed from the article on Dwarves in The Dragon #3. I had explained that with the discovery of a ritual by which the dwarves strengthened their ties to their ancient bloodlines, but I guess that either the ritual only affected a limited number of dwarves, or it wore off eventually.)
There is also some extra detail on Mountain Dwarves (with Hill Dwarves being the default type). Generally they are bigger, get an extra hit point, and use fewer crossbows and more spears.