Check Out Collectibles on Destiny 2 Wiki
Calcified Fragments - Collect all 50 of them in The Dreadnaught. 45 is needed for Touch of Malice.
Crucible Medals - Medals for completing specific goals and objectives in The Crucible (PvP). Some of the Medals are required to complete certain Crucible Bounties.
Dead Ghosts - Dead Ghosts are decommissioned Ghost objects scattered across the Destiny universe. Players can find these Ghosts and unlock corresponding Grimoire Cards related to their lore.
Dormant SIVA Clusters -
Easter Egg Coins - Easter Egg Coins are Destiny coins hidden in The Tower. They have no effect and cannot be interacted with.
Grimoire Cards - Cards unlocked by reaching certain milestones in game. These cards not only reveal lore and stories of Destiny universe but also have in-game bonuses. Players can view their unlocked cards from Bungie website.
Gold Chests - Each planet has 5 Gold Chests scattered throughout its landscape. Players can only collect each of these chests once. Occasionally they offer rare awards such as emblems or sparrows.
Perks - Class Perks, Armor Perks, Weapon Perks, Weapon Barrels, Weapon Sights.
PlayStation Trophies and Xbox Achievements - Trophies and Achievements give PlayStation and Xbox achievement points when they are unlocked.
Redemption Codes - Redemption Codes are codes that can be entered on Bungie.net to unlock Emblems, Shaders and Grimoire Cards.