Dragon Magazine
Dragon Magazine was, alongside Dungeon Magazine, one of the two official monthly magazines supporting D&D. It was in print from 1976 - 2007 published by paizo, then bought back by WOTC and published as a PDF support of 4e. It was quietly put out of its misery in 2013 when 5th edition became a thing, and probably won't be back any time soon. Who the fuck buys dead trees in 2016?
We can all blame Hasbro, of course. Soul-less, emotion-less automatons that they are. Like passively malicious modrons.
Over its venerable 31-year run, Dragon Magazine was responsible for providing a huge amount of content. Although some aspects proved only short-lived (Giants In The Earth, for example, an article that converted real-world or fantasy novel/game characters to D&D statblocks, didn't make it to the 3e switchover), it provided a huge array of races, magic items, spells, feats, classes, and other crunchy goodness of... admittedly somewhat variable quality.
In fact, the content of pre-4e Dragon content is so huge that there's actually a website that tries to serve as an encylopediac reference for the whole mess, which you can find here: http://www.aeolia.net/dragondex/