All that's available in this world is 26 dirt/grass, an oak tree, one lava source, and an unfilled End frame. That's right, no obsidian or water. With the release of 1.17.1, you can still get to the Nether and End, although it will be challenging. Do you have what it takes to complete this map by defeating both the Wither and the Ender Dragon? There are endless possibilities with this map: you can even get Elytra

The map is centered at 0,0 and extends 2048 blocks in all directions. All bounding boxes for structures are the exact same as the seed. Lava source and frame are directly below the island.

My Playthrough:

Seed: -3869947219072412705

Progression

Get Iron from Zombies
Craft Cauldrons and Collect Rain Water
Make a Cobblestone Generator
Smelt down Gold Armor and get Golden Apples
Cure Villagers using a Witch's Weakness
Trade for Emeralds
Get a Wandering Trader that sells Dripstone
Create Infinite Lava
Make Obsidian and go to the Nether
Farm Fortress Mobs
Kill the Wither/Ender Dragon
Get Elytra and Create the Skyblock of your Dream

Credits

Noobcrew: for the concept of Skyblock
SeedSearcherStandAloneTool: For finding the seed
NBTExplorer: For use in making the map
Icons8.com: For the amazing map icon
Protosky Mod: For world generation with bounding boxes

Skyblock Extreme