My goal is to remove all existing Elytras from our server (only on the overworld, but not much of a problem otherwise, since we can just respawn the end).
I read about the command
/kill @e[type=Item] on reddit. It did not work for me somehow. I tried it using:
/kill @e[type=elytra] and got the message "Selector '@e[type=minecraft:elytra]' found nothing. Entity type type 'minecraft:elytra' is invalid". I took one out of the chest, threw it on the ground, but I get the same message.
The entity type cannot be invalid IMHO, since
/give <playername> elytra works.