I’ve been haunted by this idea since yesterday so there it is, all Destiny characters who died and then it was revealed they were still, in one way or another, alive (in no particular order):
Taniks, the Scarred - a classic. died four (five?) times and it’s inferred he’s not quite done yet because I heard that after you defeat him in DSC you can still hear him laugh
Omnigul - died, then canonically came back (“undid her death”), which infers she has a throne world, and as we have yet to kill her in her throne world, she’s most likely still vibing there
Saint-14 - we’ve SEEN his grave, then Season of Dawn happened
Tevis Larsen - we see his body in the Black Garden, then years later Aspect is released and tells us how his consciousness is in fact very much alive and trapped there
Praedyth - we see his skeleton in the Vault, then, once again, Aspect is released and tells us he is still in some way trapped there. Now time is a blurry mush when the Vex are involved, but I believe what’s happening in Aspect is being caused by either the Darkness closing in on Sol or the Lunar pyramid stirring - so as this is a paracausal force, it can very well mess with Praedyth’s fate and allow him to escape the Vault safely before he dies there. If you want to debate this, @ing me is very welcomed!!
Ir Yût - we kill her in Crota’s throne world, but then she can be seen attending his death ceremony in TTK
The Undying Mind - the name says it all. We kill it twice in D1 and then it comes back yet again in Season of the Undying
Xol - we kill him in Warmind, but in the Whisper mission he still whispers to us and it’s inferred he actually lives, in some way, within the Whisper of the Worm sniper rifle
Mara Sov - she literally died in TTK and came back only because she found a way to escape into Oryx’s throne world and then into her own
Toland - he died (at least his body was sundered) but then also Ascended and is now an orb
Omar Agah - Eris (and all of us) believed him to be dead, but then we learn in Shadowkeep he’s actually a bug
Asher Mir - the Exodus quest and lorebook made it seem like he died, but then the friendly Harpy morse-codes “ASSISTANT” to us, so like… you know
Ana Bray - believed to be dead at Twilight Gap, turned out to actually be in hiding so she could discover her past
Lady Efrideet - believed to be dead by everyone including her closest friends (Saladin and Tyra), turned out to have run off to form a pacifist colony in the outer system
Nokris - we kill him in Warmind, he later comes back in Season of Arrivals
Sepiks Prime - we kill him in D1 vanilla, in RoI is ressurected by SIVA
Atheon - we canonically kill him again in TTK as a part of the No Time to Explain quest
Techeun Shuro Chi - believed to have died in the battle of Saturn, turned out she was Taken and later freed by Guardians
Techeun Sedia - same as above
Techeun Kalli - same as above
Paladin Leona Bryl - believed to have died in the battle of Saturn, turned out she survived and later was supportive of Petra in the political clash about whether she should take the position of Queen or not
Urzok, Aspect of Hate - formerly Urzok, the Hated, killed by Guardians and later resurrected and Taken by Xol, fought again in the Whisper mission
Drevis, Aspect of Darkness - formerly Drevis, Wolf Baroness, killed by Guardians and later resurrected by Xol in the same manner as Urzok
Ta'aurc, Aspect of War - formerly Valus Ta’aurc (yes, the Valus Ta’aurc), killed by Guardians and later resurrected by Xol. He is encountered yet again in Dares of Eternity, and from Xûr’s words it appears he recognises his killer so it’s still the same person
Crota - killed by Guardians, encountered again in Dares of Eternity - from Xûr’s words it appears he recognises his killer so it’s still the same person
Zydron, Gate Lord - same as above
This list is, by no means, complete, because Bungie can’t keep a corpse a corpse and we will probably see more of dead characters returning to life in the future.