This pdf is 23 pages long, 1 page front cover, 1 page editorial, 1 page SRD, 2 pages advertisement, leaving us with 18 pages of content, so what kind of dragons do we actually get?
The pdf kicks off with a short IC-introduction and a list that lists the new variants according to the base draconic race they modify -variant dragons for all the basic chromatic and metallic dragons are provided. Essentially, the variant dragons are presented as archetypes or a kind of mini-template - essentially, they replace standard abilities of their base draconic race with a new abilities and modifications. Better yet, each entry provides its introduction written in-character and often is a plot-hook on its own. As a bonus, we also get spelled out plot hooks to craft adventures from.
Now, if you think these dragons are simple "replace x with y", you'll be positively surprised - I know I was: From the very first dragon on, the Bell Metal Dragon, a variant of the Bronze - attuned to the very vibrations of the multiverse and its infinite cadence, these beings are immune to sound, reverberate with deadly resonances when hit with melee weapons and can also emit deadly thunderous roars. The majestic golden crown dragons, exalted even by the standards of their noble kin, can declare a being to be a vassal, possessing the being and temporarily granting the being the half-dragon template. The Blue wingless Dune Dragons are perfect desert hunters, swimming through the sands, while red furnace dragon may not be able to breathe fire, but have a devastating, all-destroying swallow whole attack.
There also are rather cool and unique ones among these mini draconic templates, first and foremost for example the Hydra-dragon, a variant black dragon with multiple regenerating heads that come at the expense of the powerful natural attacks such dragons usually have. Another favorite of mine would be the bronze variant orichalcum dragon, which can use its breath to enhance its electricity aura and later even add the cold iron and lawful qualities to its attacks. Also neat, the Petrified green dragons with their breath that may turn their foes to stone, while the chaotic neutral Pyrite Gold Dragon may make for some unpleasant surprises for those too trusting in the purity of these paragons of dragonkind, while the root-gnawing dragon would be especially appropriate for norse-tinged campaign, being able to gnaw a Yggdrasil's roots, i.e. tearing gates into the fabric of reality. And then there are the Void dragons - whites that thrive in the airless, cold void between stars and can act as emissaries between cultists and their masters from the Dark Tapestry. And that's just to give you a glimpse of what to expect herein.
Editing and formatting are good, though I did notice some glitches, none seriously impeded my enjoyment of the pdf. Layout adheres to RiP's 2-column full color standard and the full color depictions of some of the dragons are nice, even though you might already be familiar with some. The pdf comes with extensive bookmarks.
I was honestly surprised by this pdf - I mean, come on, what can you expect in such scant few pages? I was sincerely dreading boring "exchange element a for element b" and similar changes. Instead, author Eric Morton has created a cool gamut of draconic abilities that not only come with well-written prose and are mechanically sound, but also serve their respective niches in a campaign and feel like they do organically belong - whether as mutations or full-fledged species, these beings will enhance the draconic glory in your campaign, enrich the concept of dragons and enable you to pull off new plots - reading the Pyrite dragon and the Void Dragon, for example, made me smile and cackle with glee. However, the editing glitches, while not crucial, are a slight deterrent when reading this book and thus my final verdict will be 4.5 stars, rounded down to 4 for the purpose of this platform.
[4 of 5 Stars!]