The Ishtar Collective has basically every piece of lore ever put into both games. It is a massive collection of Destiny’s history and you’ll enjoy going down the rabbit hole and spending hours learning the reasons why everything is happening.
The undisputed Historian of the Destiny Universe. My Name Is Byf’s videos will submerge you in the lore of Destiny and are a brilliant choice for anyone who wants to listen to the history instead of reading it.
Aside from being a great resource in general, Destinypedia has all the lore laid out in full Wikipedia form making it much easier to read than in-game. This includes lore from Weapons and Armor Sets allowing you to deep dive into the history of this universe.