Minecraft wiki entry for Best_biomes_for_homes, associated text: Plenty of ender pearls. Ender pearls could be easily farmed.
Plenty of chorus plants can be collected, which, while serving as a sufficient food source, will randomly teleport the player when eaten.
An end city can provide some of the tools the player had been lacking, including enchanted iron/diamond tools and armor. The most valuable loot is the elytra, found on the flying ships in an end city. This item can make traversing the vast chasms between islands much easier. Also, the cities can be renovated or deconstructed for their unique building blocks, some of the only ones the player can obtain.
Given that both chests and shulker shells can be obtained in end cities, the player can create shulker boxes for mobile storage needs.