Destiny Emblem Collector is the most complete source for Destiny emblems: what they look like, exactly how to get them, and whether they're still available.
DEC currently tracks 935 Destiny 2 emblems and 271 Destiny 1 emblems.
There are a few different places to get updates/patch notes from DEC and emblem news. All of these different places should have the same info posted to them, so follow wherever you spend your time!