So, I've always been interested in dragon-descended characters, so I wanted to look into how they've developed through different editions of DnD. My experience has mostly been in 3.5 and 4e, as well as PF, so I'll present what I know from those editions. Further information is of course welcome.
So, 3.5 core had half dragons, alongside sorcerers having "dragonblood" as one of the default fluff options. The MM also had kobolds, who were now little lizard type people who spoke draconic instead of the dog-people I remember from Baldur's Gate. The DMG presented the Dragon Disciple for sorcerers and bards to become half dragons (and inspiring schrodinger's half dragon). As things expanded, we got Races of Dragon with Dragonborn of Bahamut (kind of an adopted dragonblood), Spellscales (I don't actually remember their origin and don't have access to my copy right now), and Kobolds expanded into being proper dragonblood. We also got a fiendish/celestial parallel with the draconic creature template. Dragon Magic brought in the dragontouched races and feat, allowing anyone to have a little dragon in them, along with the Dragonfire Adept class for people who want to explore that heritage. I'm sure Draconomicon had some information, but sadly that was never a book I had.
Pathfinder expanded Sorcerer to draw power from the different bloodlines, including draconic, and likewise presented us with the bloodrager for a more primal take on things. But from what I've seen, PF has done fairly little with draconic races, with kobolds getting a bit of token support and not much else.
DnD 4e had the dragonborn race as an independent species, rather than a hybridized race. They also codified the Dragon Magic Sorcerer. But my experience with 4e has mostly been on the player side, in home games, so I'm not sure how much, if at all, dragon descended were expanded on in published modules and novels.
So I guess the question here is: What am I missing? What dragon-descended content was present in the early years of DnD, and what has 5e brought to our illustrious tables? What aspects of dragonkin did I miss in the editions I have played?