劇透 - :
So if you're (not) like me and you don't have the time or patience to watch Spoilers & Swag, you may have missed this awesome reveal... Gem Dragons are back! And I don't just mean back in a third-party book like Matt Colville's Strongholds and Followers (great book, check it out), I mean back officially for D&D 5e.
In case you don't know, Gem Dragons are the third-wheel of dragonkind... they are not Good (Metallic) or Evil (Chromatic), they are Neutral. This makes them easily overlooked in the struggle of good vs. evil, but they've popped up here and there in previous editions.
But it looks like Gem Dragons have returned, first to promote the sale of a very expensive sapphire dice set. This little paper fold-out is included (screenshots below), complete with lore for gem dragons and a statblock for the Adult Sapphire Dragon specifically.
Of course, if you don't want to buy a pricey set of dice for a statblock... you're in luck, as Nathan Stewart reveals that everybody else will get access to it "early in 2020, where we [WotC] will have some fun ways to get that out there." So it looks like some product will be released including the Neutral Dragons, a new adventure or maybe a new monster book!
Feel free to speculate, here's the images;