How to get items from End City to the Overworld?

Solution 1:

The easiest way to get your items back is through an ender chest. Since ender chests "teleport" items to other ender chests throughout the world, you can craft an ender chest, place it in the end, and dump all of your items inside. Then, commit suicide by jumping into the void (the only thing you'll lose is some XP). Once you respawn in the overworld, craft another ender chest and retrieve your items.

Crafting one is easy: Surround an Eye of Ender with obsidian in a crafting table. Since you're in the end, these materials should be very easy to get.

As far as I know, there is no reasonable way to automatically transport items back to the overworld.