Shaders from the regular activities like Strikes (Vanguard Divided from season 4), Crucible/Iron Banner, Raids, ect. Even from shelved activities like Trials of the Nine recycled into the Prophecy dungeon since they both share the same theme. As well as Faction Rallies and early year activities like the Menagerie and Season of the Worthy. That way new and returning players aren't locked out from palettes to customize their Guardians.