If we exist to make others exist then our existence is pre-existence, and every other existence to be and to have been is a pre-existance and we don't matter because we are setting up the world for the generation that matters... we're doing a pretty terrible job at it atm tho.
Or we could just take the easier and more likely way out and and admit we are in a simulation but nah.

Fandoms:
The trio+
Sherlock 
Full metal alchemist 
Classroom of the elite
Mystic messenger (yes the fandom still exists)
TØP 
Naruto
Voltron
Magi:labyrinth of magic
Pandora hearts
Case study of vanitas
Fairy tail
To your eternity 
Harry Potter
Maze runner 
Divergent
Eragon 
Bungou stray dogs
404 army
NF
No game no life
Angel beats
Another
Chalotte
Noragami 
Kakegurui
Ass class
Owari no seraph
No.6
Nurahiyon no mago 
Nanbaka
Terror in reasonance 
League of ledgends
Tokyo ghoul 
VR chat
Marvel comics
MCU
DC
Soul worker
CSGO
+ more but I cba to type